Skin and soft tissue infections - inside by hjkuiw354


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                                                                                                                                                                                                                     Folliculitis and
                                                                                                                                                                                                                     skin abscesses


                                                                                                                                                                                                                     Diabetic foot

                                                                                                                                                                                                                     Deep complicated
                                                                                                                                                                                                                     skin and soft
                                                                                                                                                                                                                     tissue infections

                                                                                                                                                                                                                     skin conditions

                                                                                                                                                                                                                     The authors

                                                                                                                                                                                                                      DR BERNIE HUDSON,

Skin and
                                                                                                                                                                                         MRSA bacteria.
                                                                                                                                                                                                                      senior staff specialist,
                                                                                                                                                                                                                      department of microbiology and
                                                                                                                                                                                                                      infectious diseases, Pacific
                                                                                                                                                                                                                      Laboratory Medicine Services
                                                                                                                                                                                                                      (PaLMS), Royal North Shore
                                                                                                                                                                                                                      Hospital, Sydney, NSW; senior

soft tissue infections
                                                                                                                                                                                                                      lecturer, department of
                                                                                                                                                                                                                      infectious diseases, Sydney
                                                                                                                                                                                                                      University; and visiting associate
                                                                                                                                                                                                                      professor, James Cook
                                                                                                                                                                                                                      University, Townsville, Qld.

THE most common skin and soft               because of these infections. There is      ‘diseased’ skin affected by conditions                           Infections can be caused by a host
tissue infections in humans are bacter-     evidence that infection rates are          such as dermatitis.                                            of agents, including fungi, parasites
ial. Although incidences for these infec-   increasing in certain groups, such as         Systemic illness should also be con-                        and viruses. However, this article
tions in Australia are unknown, they        the elderly.                               sidered as a cause of local signs (for                         focuses on bacterial skin infections,                          DR SEBASTIAAN VAN HAL,
account for about 10% of all hospital         Local skin infections occur because      example, ecthyma gangrenosum sec-                              ranging from the trivial to the some-                          registrar, department of
admissions in the US, and data from         of a breach in the skin: primary           ondary to pseudomonas bacteraemia in                           times lethal. Successful outcomes rely                         microbiology and infectious
the UK suggests that 0.1% of the adult      infections occur in normal skin,           a neutropenic patient, or the skin man-                        on early recognition and initiation of                         diseases, PaLMS, Royal North
population is hospitalised annually         while secondary infections occur in        ifestations of infective endocarditis).                        appropriate therapy.                                           Shore Hospital, Sydney, NSW.

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                                                                                                                                                                  16 September 2005 | Australian Doctor |                     25
GENERAL management of               Figure 1: Categorisation of skin and soft tissue infections by                                                                                                  seas in rabies-endemic areas
                                                                                                                      Table 1: Types of skin infections, with corresponding
non-infected wounds depends         skin layers affected.                                                                                                                                           and for bat bites and
                                                                                                                                commonly associated pathogens
on the level of associated risk.                                                                                                                                                                    scratches acquired in Aus-
Low-risk wounds do not                                                                                                Category                                  Common pathogen                     tralia or overseas.
require antibiotics. These
include mild wounds that:
n Do not involve deeper
                                     Epidermis       {                                       {    Impetigo            Impetigo (epidermis)                      S pyogenes                          Definitions
                                                                                                                                                                                                    The terminology used for

                                                                                                                                                                S aureus

  structures (ie, bone, joints                                                                                                                                                                      skin and soft tissue infec-

  and tendons).                                                                                   Erysipelas          Folliculitis, skin abscesses              S aureus                            tions is often confusing.
n Are less than eight hours                                                                                                                                                                            Generally these infections
                                                                                                                      and furuncles (hair follicle)
  old.                                    Dermis                                                                                                                                                    are categorised by the layer
n Can be adequately debrided,                                                                                         Cellulitis (epidermis, dermis,            ß-haemolytic streptococci           of the skin (the epidermis,
  irrigated and dressed.                                                                                              subcutaneous fat)                         S aureus                            dermis and/or subcutaneous
   High-risk wounds require                                                                       Necrotising                                                   Other                               tissue) that is invaded by the
antibiotic therapy and the
choice of antibiotic is deter-
mined by the clinical setting.
                                          follicle                               {           Sweat
                                                                                                                      Necrotising fasciitis                     S pyogenes
                                                                                                                                                                Mixed bowel flora
                                                                                                                                                                                                    microbial organism (figure
                                                                                                                                                                                                       For example, impetigo is
These wounds have one or                                                             Nerve                                                                                                          usually limited to the epider-
more of the following fea-                      Subcutaneous         Oil gland                                        Clostridial myonecrosis (muscle)          Clostridium perfringens             mis; cellulitis occurs in the
tures:                                                 tissue                                                                                                                                       epidermis, dermis and sub-
n Eight or more hours old.                                                                                                                                                                          cutaneous fat, while
n Puncture wounds that                                                       n A history of underlying              taken, and delayed primary               appropriate (see Australian            erysipelas is cellulitis limited
  cannot be adequately                                                         immunosuppression.                   skin closure may be appro-               antibiotic guidelines and the          to the dermis alone; and
  debrided.                                                                     Established wound infec-            priate.                                  Australian Immunisation                necrotising fasciitis is a
n Wounds on the hands, feet                                                  tion requires antibiotic ther-            It is important to assess             Handbook ).                            severe infection involving the
  or face.                                                                   apy, appropriate wound                 tetanus immunisation status                Expert advice about post-            subcutaneous tissues. Each
n Involvement of underlying                                                  care and surgical manage-              and administer tetanus                   exposure prophylaxis should            category of infection is asso-
  structures (ie, bones, joints,                                             ment as necessary.                     toxoid, with or without                  be sought for animal bites             ciated with typical organisms
  tendons).                                                                     A wound swab should be              tetanus immunoglobulin, as               and scratches acquired over-           (see table 1).

 Common skin and soft tissue infections
Impetigo                                                 Table 2: Antibiotics used in soft tissue and skin infection                          area. P aeruginosa or mycobacterial            otics, so each case should be judged
IN the past, Streptococcus pyogenes                                                                                                           species (for example, Mycobac-                 individually.
(group A streptococcus) was consid-            Amoxycillin-clavulanate       Augmentin, Clamohexal, Clamoxyl, Clavulin                        terium chelonae) have been impli-                 Hidradenitis suppurativa, caused
ered the principal cause of impetigo,          Benzathine penicillin         Bicillin LA                                                      cated in folliculitis associated with          by keratinous plugging of apocrine
accounting for 80% of isolates. How-           Cephalexin                    Cephazolin, Cilex, Ialex, Ibilex, Keflex,                        the use of hot tubs or jacuzzis.               glands of the axillae or inguinal
ever, rates of streptococcal infection                                       Sporahexal                                                          Pseudomonas folliculitis lesions,           regions, usually requires no treatment
have fallen to 20-30% and been sur-            Clarithromycin                Clarithromycin, Clarac, Kalixocin, Klacid                        often seen in areas covered by the             unless secondary infection occurs.
passed by staphylococcal infection.            Clindamycin                   Cleocin, Dalacin C                                               swimming costume, usually settle               Antibiotic selection should be based
   The characteristic skin lesion in           Ciprofloxacin                 C-Flox, Ciprofloxacin-BC, Ciprol, Ciproxin,                      without treatment. The main man-               on the bacteriology of aspirated
impetigo starts as a small vesicle that                                      Profloxin, Proquin                                               agement is avoiding the spa until it           lesions, as there are multiple causes,
rapidly becomes pustular and rup-              Dicloxacillin                 Diclocil, Dicloxsig, Distaph                                     has been cleaned thoroughly. If the            including S aureus, anaerobes and
tures, leaving a moist red surface.            Erythromycin                  Erythromycin, E-Mycin, EES, Eryc, Erythrocin IV                  lesions do not improve, oral cipro-            Gram-negative organisms, including
The discharge dries and typically              Flucloxacillin                Aspen Flucil, Flopen, Floxapen, Floxsig, Flubiclox,              floxacin is the preferred antibiotic.          P aeruginosa. Refractory cases may
forms a characteristic crust, honey-                                         Staphylex                                                           Decontamination of the hot tub              require surgical management.
coloured in streptococcal infection            Linezolid                     Zyvox                                                            requires professional advice. Chlori-
and varnish-like in staphylococcal             Metronidazole                 Flagyl, Metrogyl, Metronidazole, Metronide                       nation alone is inadequate. Thorough           Treatment
infection. In children these lesions           Minocycline                   Akamin, Minomycin                                                cleaning of the spa and filters is very        Standard anti-staphylococcal antibi-
often occur on the face, especially            Mupirocin                     Bactroban                                                        important, because the organisms               otics (dicloxacillin/flucloxacillin or
around the mouth and nose.                     Rifampicin                    Rifadin, Rimycin                                                 usually persist in biofilm that coats          cephalexin) remain the empirical
   Staphylococcal impetigo lesions,            Fusidic acid                  Fucidin                                                          surfaces.                                      antimicrobial choices for skin
mediated by a local response to one            Roxithromycin                 Biaxsig, Rulide                                                     Antimicrobial therapy is usually            abscesses in association with the
of two exfoliative toxins, tend to be                                                                                                         required when the cause is a                   appropriate surgical procedure (usu-
larger and bullous, hence the name           otics are usually sufficient to cover           ments for impetigo, so it is debatable           mycobacterium. A variety of combi-             ally incision and drainage).
bullous impetigo. This primarily             both streptococcal and staphylococ-             whether topical mupirocin should be              nation antibiotic regimens can be                 However, the recommendations
occurs in children and is rare in            cal causes.                                     used in this manner.                             used but specialist advice should be           for empirical antibiotic therapy may
adults, as the targets for the toxins           Dicloxacillin/flucloxacillin or                In refractory cases, underlying                sought, because laboratory suscepti-           change if the incidence of infection
disappear with age and antibodies            cephalexin can be used (roxithro-               dermatological conditions such as                bility tests do not predict clinical out-      with community-acquired multi-resis-
provide protection against local and         mycin or clarithromycin are alterna-            scabies and head lice should be                  comes reliably.                                tant S aureus (see below) becomes
systemic disease.                            tives for patients with penicillin              excluded. In remote areas, IM ben-                  A furuncle (boil) is a deep inflam-         high enough to warrant clindamycin
   A systemic form of this disease,          allergy) while awaiting culture and             zathine penicillin (Bicillin LA) may             matory nodule that usually develops            as initial empirical therapy.
staphylococcal scalded skin syn-             susceptibility results (see table 2).           overcome compliance issues.                      from preceding folliculitis. A carbun-            When unusual causes are suspected
drome, is mediated by the same two              Removal of crusts twice daily                                                                 cle (skin abscess) is a more extensive         (for example, specific exposure and/or
exfoliative toxins and characterised         (with saline, soap and water, alu-              Folliculitis and skin abscesses                  infection with multiple connecting             disease refractory to standard ther-
by widespread bullous skin lesions           minium acetate solution or potas-               Most cases of folliculitis are caused            furuncles affecting the subcutaneous           apy), specimens should be collected
with exfoliation. Patients with this         sium permanganate) and topical                  by S aureus, but other causes include:           tissue. These lesions predominate in           for culture to help guide therapy.
suspected infection require urgent           mupirocin 2% tds for seven days are             n Pseudomonas aeruginosa.                        skin areas that contain hair follicles            Discussion with the clinical micro-
hospital admission.                          usually recommended.                            n Candida.                                       and are subject to friction and per-           biologist is advisable to ensure the best
   Given the classic appearance of              Although topical mupirocin has               n Mycobacteria.                                  spiration, such as the neck, face, axil-       specimen is collected, transported and
impetigo, investigations are often not       been clearly shown to be associated             n Fungal infections, including infec-            lae and buttocks. Predisposing fac-            processed. This commonly includes
done, but, since streptococcal               with the emergence of resistant                   tion with Malassezia furfur (a                 tors include diabetes and obesity.             biopsy for culture and histopathol-
impetigo requires systemic antibiotic        strains of Staphylococcus aureus in               lipophilic yeast responsible for                  Furuncles and carbuncles are usu-           ogy: biopsy may detect non-infective
treatment, a swab is advised. Topical        the treatment of skin and soft tissue             pityriasis versicolor), follicular             ally caused by S aureus. Although              skin conditions (for example, pyo-
therapy (see below) is often adequate        infections, it is still commonly rec-             pityriasis, seborrhoeic dermatitis             they may be associated with systemic           derma gangrenosum) that do not
for local lesions when a staphylococ-        ommended for impetigo.                            and pityriasis capitis.                        features and bacteraemia, most cases           respond to antibiotic treatment.
cal cause is suspected or proven.               This may not be ideal treatment              n The human follicle mite Demodex                present without systemic toxicity and
   The potential for post-streptococcal      but it may be justified by the fact               follicularis.                                  the lesions respond to application of          Community-acquired multi-resistant
glomerulonephritis complicates this          that, in one meta-analysis of com-                 Hair follicle infection can occur             hot packs, incision and drainage.              S aureus
management so that, if in doubt,             bined staphylococcal and streptococ-            spontaneously or be associated with                 Although antibiotics are usually            In the past, MRSA was used to refer
antibiotics for streptococcal impetigo       cal impetigo, topical mupirocin had             the use of exfoliative beauty aids,              given in such cases, they do not               to methicillin-resistant S aureus.
should be given, pending the swab            higher cure rates than placebo and              such as loofah sponges, or shaving.              appear to shorten the course of ill-           More recently, it has been used to
culture result.                              was superior to oral erythromycin,                 Lesions are usually small pruritic            ness. While they theoretically reduce          describe resistance of the bacterium to
   While penicillin is the preferred         which was superior to oral penicillin.          papules, often topped with a central             the risk of bacteraemia, in practice           multiple antibiotics.
antibiotic therapy when S pyogenes is           However, there have been few                 pustule. A severe chronic form, syco-            it may be difficult to determine who             Infection with community-acquired
present, anti-staphylococcal antibi-         placebo-controlled trials of treat-             sis barbae, can occur in the beard               should or should not receive antibi-                                  cont’d next page

                                                                                                                                                     16 September 2005 | Australian Doctor |    27
 How to treat – skin and soft tissue infections

 from previous page                                                                                                                                                               associated risk of relapse and
 MRSA (CA-MRSA) strains is                                                                                                                                                        re-presentation for a formal
 an emerging problem. CA-                                                                                                                                                         hospital admission.
 MRSA strains contain various                                                                                                                                                        Initial investigations depend
 virulence factors (for example,                                                                                                                                                  on the severity of the infection
 the Panton-Valentine leuko-                                                                                                                                                      and should include:
 cidin gene) that confer a                                                                                                                                                        n FBC (especially neutrophil

 propensity to form abscesses,                                                                                                                                                      count).
 particularly in the skin. Sys-                                                                                                                                                   n Renal function.

 temic infection with a fulmi-                                                                                                                                                    n Inflammatory markers such

 nant onset and subsequent                                                                                                                                                          as C-reactive protein.
 death after seemingly minor                                                                                                                                                         Blood cultures should be
 skin abrasion and infection has                                                                                                                                                  collected in all patients with
 been reported in otherwise                                                                                                                                                       systemic features even though
 healthy young people.                                                                                                                                                            bacteraemia occurs in fewer
    The definition of a CA-                                                                                                                                                       than 10% of cases. Cultures
 MRSA strain differs between         Hand injuries caused by shark bite. High-risk bites on the hand        Dog bite on the hand of an asplenic individual resulted in this       may provide invaluable assis-
 publications, but the essential     require antibiotic therapy. In this case, antibiotic cover for         local lesion and bacteraemia with hypotension and severe illness.     tance by showing unusual
 characteristics are a resistance    saltwater-borne organisms was given in addition to surgical            Capnocytophaga canimorsus was isolated from blood cultures.           pathogens or common ones
 to standard anti-staphylococ-                                                                                                                                                    with unexpected antibiotic
 cal antibiotics (such as                                                                                                                                                         susceptibilities.
                                             Table 3: Risk
 cephalexin and flucloxacillin)                                                                                                                                                      Immunosuppressed patients
                                       factors/groups at high
 and a continued susceptibility                                                                                                                                                   are at particular risk of infec-
                                          risk for CA-MRSA
 to clindamycin and/or ery-                                                                                                                                                       tions with an atypical presen-
                                            skin infections
 thromycin.                                                                                                                                                                       tation or caused by unusual
    Rates of infections due to        n   Playing contact sports                                                                                                                  pathogens. In this group and
 CA-MRSA are increasing and           n   Indigenous Australians                                                                                                                  in patients with unusual expo-
 should be considered in cer-                                                                                                                                                     sure, skin biopsy specimens
                                      n   Institutions:
 tain risk groups (table 3),                                                                                                                                                      may be required for fungal
 including patients who partic-           — prisons                                                                                                                               and mycobacterial cultures as
 ipate in contact sports (eg,             — day care centres                                                                                                                      well as standard bacterial cul-
 rugby, wrestling). Sharing-              — centres for people with                                                                                                               tures. Collection of fluid aspi-
 towels or spas and failing to              developmental                                                                                                                         rated from a blister may also
 use sterile techniques in med-             disabilities                                                                                                                          provide a microbiological
 ical aid contribute to this risk.                                                                                                                                                diagnosis.
                                      n   IV drug use
    All patients who fall into                                                                                                                                                       The benefits of obtaining
 high-risk groups and present         n   Men who have sex                                                                                                                        specimens for culture in all
 with skin abscesses should               with men                                                                                                                                patients are debatable. Open-
 have a swab taken of a (prefer-      n   Military recruits                                                                                                                       wound swabs often yield
 ably) purulent skin lesion.                                                                                                                                                      organisms of dubious signifi-
    In patients with confirmed                                           A skin lesion with unusual appearance that was not responding to standard antibiotic therapy.            cance but can be more helpful
 CA-MRSA or those for                     Table 4: Host factors                                                                                                                   when an uncommon pathogen
                                                                         Biopsy for culture yielded Mycobacterium marinum after 10 days' incubation. Histopathology
 whom conventional therapy                 that predispose to                                                                                                                     is suspected because of partic-
                                                                         showed granulomatous appearance but stains for acid-fast bacilli were negative.
 fails, clindamycin is usually                  cellulitis                                                                                                                        ular exposure (for example,
 the drug of choice, but sus-         n   Lymphoedema                    applied with a face cloth or       well-demarcated border.            with sudden onset of fever         water-associated injury or
 ceptibility results are impor-       n   Leg ulcer (venous or           disposable sponge, which              Although S aureus and           and no localising signs.           wound when Aeromonas or
 tant. For therapeutic purposes,          arterial)                      should be single-use only. The     Gram-negative and Clostrid-           Several risk factors, such      Vibrio species are suspected).
 strains that are resistant to        n   Previous cellulitis            face cloth should be washed        ium species are rarer and          as lymphoedema, predispose            Obtaining specimens may
 erythromycin but susceptible                                            in hot water before it is          difficult-to-exclude causes,       patients to developing cel-        aid in directing therapy in
 to clindamycin on laboratory
                                      n   Tinea pedis                    reused. Patients should pay        the clinical setting may give      lulitis (table 4).                 high-risk patients for CA-
 tests should probably be             n   Traumatic wounds               particular attention to the        the clue to the involvement           The first step in managing      MRSA colonisation and
 regarded as clindamycin resis-       n   Recent surgery                 axillae, inguinal and perineal     of non-streptococcal agents.       a patient with cellulitis is to    those who have recently
 tant, as >90% of such strains        n   Radiotherapy
                                                                         regions.                              For cellulitis extending        decide if they require referral    been discharged from hospi-
 usually possess inducible resis-                                           All bed linen, towels, wash     into the subcutaneous tissues,     or hospitalisation. Factors        tal (within two weeks), espe-
 tance to clindamycin not
                                      n   Scabies                        cloths and suitable clothes        the most common causes are         guiding this decision are          cially if their stay involved a
 detected by standard suscepti-                                          should be washed in hot            S pyogenes and S aureus.           listed in table 5.                 period in intensive care.
 bility tests.                                                           water. Other clothes should        Other rarer pathogens can             All patients who have           These patients are invariably
    In general practice, other
                                          Table 5: Patient factors       be steam- or dry-cleaned or,       cause cellulitis but usually       severe progressive cellulitis,     colonised with characteristi-
 treatment options, if sup-
                                           that guide admission          if this is not possible, washed    occur in the context of spe-       possible muscle involvement        cally multi-resistant hospital-
 ported by susceptibility results,
                                              and/or referral            and hung in the sun to dry         cific exposures or settings        or signs of severe sepsis should   acquired organisms such as
 include co-trimoxazole or            n   Poor response to antibiotic    completely.                        (see table 4).                     be admitted to hospital. Severe    MRSA and P aeruginosa.
 minocycline. Some antibiotics,           treatment in the preceding        The water temperature              Some of these skin infec-       sepsis is suggested by any two        The antibiotic choices for
 such as rifampicin (in combi-            two weeks because of a         required for washing is higher     tions have a typical presenta-     of the following:                  treating these organisms are
 nation with fusidic acid) or             pre-existing condition         than that at which domestic        tion but others can be associ-     n Tachycardia.                     limited and IV therapy may be
 the new antibiotic linezolid             (diabetes, obesity, arterial   hot water systems are usually      ated with severe, potentially      n Hypotension.                     required. Also, patients with
 (Zyvox), are only easily avail-          or venous insufficiency,       set. In practice, using deter-     rapid progression to death if      n Confusion or decreased level     MRSA infections acquired in
 able in hospital settings, so            congestive cardiac failure,    gent, the longest cycle on the     appropriate treatment is not         of consciousness.                hospital may be discharged on
 specialist assistance may be             chronic renal or liver         washing machine and water          started in time.                   n Body temperature <35°C or        antibiotics that are either not
 required.                                failure, neoplasm,             on the hottest setting of the         The classic clinical features     >40°C.                           used or not easily obtainable
                                          neutropenia,                   domestic hot water system is       of non-erysipelas cellulitis are      When hospitalisation is not     in general practice settings.
 Recurrent abscesses                      immunosuppression,             usually adequate.                  pain, erythema and swelling        required, the next decision is
 In patients with recurrent               splenectomy, advanced             If unsuccessful, these mea-     of the lower limbs, but any        whether antibiotics should be      Treatment
 abscesses, eradication of the            age)                           sures may also need to be          site (for example, the upper       given by IV. Although this         Because most cases of celluli-
 staphylococcal carriage may          n   Extensive or rapidly           extended to family members         limb after mastectomy) can be      means hospital admission in        tis are caused by streptococci
 be achieved through:                     progressive cellulitis         and those in close contact         affected. Unlike in erysipelas,    some settings, many area           and S aureus, beta-lactam
 n General hygiene measures                                              with the patient to eradicate      the borders are usually not        health services provide home-      antibiotics with activity
                                      n   Significant systemic
   (see below).                           features (hypotension, high    the staphylococcal carriage in     raised or well demarcated and      based administration of IV         against S aureus should be
 n Mupirocin       (Bactroban)            fevers)                        the family or household            skip lesions may occur.            antibiotics (Hospital in the       the initial drugs of choice, as
   under fingernails and                                                 members (see Authors’ case            Tender regional lymphad-        Home [HITH]).                      they are also effective against
   intranasally (Bactroban nasal
                                      n   Suspicion of muscle            studies, Abscesses resistant to    enopathy is common, while             There are no guidelines or      streptococci (table 6).
   ointment) bd for 10 days.              involvement                    cephalexin and flucloxacillin,     lymphangitis tends to indicate     randomised controlled trials          No randomised controlled
 n Systemic antibiotics.              n   Lack of systemic response      page 30).                          streptococcal infection.           that compare oral and IV           trials have shown that one
    General measures include              despite appropriate                                                  Constitutional symptoms         therapy to aid in this decision,   beta-lactam antibiotic with
 showering with 4% chlorhex-              therapy                        Cellulitis                         such as fever and chills may       so in uncertain cases it may       activity against S aureus is
 idine-based body wash solu-          n   Suppurative bites or           Cellulitis is characterised by a   predate local signs or symp-       be prudent to arrange an           superior to another. However,
 tions daily for three days,              wounds, especially on face     superficial spreading bacterial    toms. In streptococcal cel-        assessment or a short initial      the patient numbers in the
 then three times weekly for at           and hands                      infection of the dermis and        lulitis these systemic signs       observation period with IV         trials were small and clinical
 least another four weeks. As         n   Positive blood cultures
                                                                         subcutaneous tissue. Infection     characteristically occur 24-       therapy in hospital.               success rates were between
 an alternative body washes                                              confined solely to the dermis,     48 hours before cellulitis            If unsure, HITH is a safer      50% and 100% for whichever
 containing povidone-iodine                                              termed erysipelas, is usually      becomes evident — a factor         option than a trial of oral        antibiotic was chosen. Simi-
 can be used.                                                            caused by streptococcal            often overlooked or forgot-        antibiotic therapy in the pri-     larly, no definitive criteria exist
    The body wash can be                                                 species and has a raised and       ten when evaluating a person       mary care setting, with its        for the duration of therapy.

28   | Australian Doctor | 16 September 2005                                       
   Generally, guidelines sug-                                                                                                                                                                       safety profile and be pre-
gest monotherapy is adequate.                                                                                                                                                                       scribed in lower doses than
The combination of penicillin                                                                                                                                                                       for acute episodes. S pyogenes
and dicloxacillin/flucloxacillin                                                                                                                                                                    does not appear to develop
to cover both ‘staph’ and                                                                                                                                                                           resistance to beta-lactams but
‘strep’ is not required in most                                                                                                                                                                     may do so with macrolides,
cases. Monotherapy with                                                                                                                                                                             although this has not been
cephalexin, dicloxacillin/flu-                                                                                                                                                                      well studied. Daily oral
cloxacillin or amoxycillin-                                                                                                                                                                         options include:
clavulanate has adequate                                                                                                                                                                            n Phenoxymethylpenicillin

activity against most strepto-                                                                                                                                                                        (penicillin V) 250mg bd.
coccal species that cause cel-                                                                                                                                                                      n Cephalexin 250mg bd.

lulitis, making the addition of                                                                                                                                                                     n Roxithromycin 150mg once

penicillin superfluous. In com-    Acute paronychia, usually due                                                                                                                                      daily (or erythromycin
plicated cases, such as diabetic   to S aureus. Surgical drainage                                                                                                                                     250mg bd) (as options for
foot infections, prolonged         is usually required, as                                                                                                                                            beta-lactam-allergic patients).
                                   antibiotics alone are usually              Diabetic foot infections requiring debridement as principal therapy after failure of antibiotic
therapy may be required for                                                   therapy alone.
                                   not curative.
underlying osteomyelitis.          (Photos provided by Dr Anthony Beard)      (Photo provided by Ian Reid, high-risk foot clinic, Royal North Shore Hospital, Sydney, NSW.)                         Diabetic foot infection
   Duration of therapy rem-                                                                                                                                                                         About 15-25% of patients
ains unclear, but data from                                                                                                                                     involves aspiration, surgical       with diabetes mellitus (espe-
                                          Table 6: Susceptibility patterns of common pathogens to antibiotics used in
outpatient IV antibiotic reg-                                                                                                                                   exploration (especially for         cially those with poor gly-
                                                         treatment of skin and soft tissue infections*
istries in the US show that                                                                                                                                     septic arthritis) and drainage.     caemic control and diabetes
therapy of longer than 3-4                                                                               Organism                                                  Malignancy and neutro-           for more than 10-15 years)
days does not correlate with        Antibiotic                             S pyogenes S aureus           CA-MRSA         HA-MRSA P aeruginosa                   philic dermatoses such as           develop foot ulceration. Risk
better outcomes. Similarly,         Amoxycillin-clavulanate                    S         S                   R              R        R                          Sweet’s syndrome (acute onset       factors include peripheral neu-
prolonged oral therapy fol-         Cephalexin                                 S         S                   R              R        R                          of erythematous skin lesions        ropathy, peripheral vascular
lowing IV antibiotics has not       Ciprofloxacin                              R         R                   R              R        S                          asymmetrically distributed          disease, abnormal foot weight
been shown to give a better         Clindamycin                                S         V                   V              R        R                          over the face, neck and             distribution and trauma.
outcome.                            Erythromycin                               S         V                   V              R        R                          extremities and often accom-           These infections are the
   Therapy duration depends         Dicloxacillin/flucloxacillin               S         S                   R              R        R                          panied by fever and a neu-          leading cause of hospitalisa-
on the individual patient ,but,     Fusidic acid                               S         S                   S              S        R                          trophilic leukocytosis) are rare    tion in patients with diabetes
generally we recommend              Penicillin                                 S         R                   R              R        R                          causes of local erythema and        and account for most lower-
antibiotics be continued for        Rifampicin                                 S         S                   S              S        R                          are usually diagnosed on            limb amputations. Prognosis
10-14 days (total of IV +           CA-MRSA = community-acquired multi-resistant S aureus                                                                       biopsy when patients fail to        depends on the adequacy of
oral), or at least until three      HA-MRSA = hospital-acquired multi-resistant S aureus                                                                        respond to treatment.               arterial blood supply. Princi-
days after the resolution of        S = susceptible (ie, usually clinically effective or susceptibility >75%)                                                      Erythema nodosum can             ples of management include:
local signs.                        R = resistant (ie, susceptibility <75%) or no data available or not recommended)                                            mimic cellulitis and present        n Assessment of severity

   Despite adequate therapy,        V = variably susceptible (institutional or geographical variations)                                                         with raised, tender, localised        (limb- or life-threatening).
local signs and symptoms may                                                                                                                                    discrete lesions. However, it       n Diagnosis of any osteo-

progress to blistering and local    Practice points                                                                                                             commonly occurs bilaterally           myelitis (see below).
                                    n S pyogenes is universally susceptible to penicillin and cephalosporins but there have been rare
necrosis. Lack of resolution of                                                                                                                                 and is therefore usually distin-    n Revascularisation           (if
systemic signs may indicate           reports of macrolide resistance                                                                                           guishable from cellulitis (see        required and if possible).
                                    n Non-MRSA strains of S aureus are universally susceptible to dicloxacillin/flucloxacillin and cephalexin
one of several possibilities:                                                                                                                                   table 7).                           n Eradication of infection
                                    n MRSA infection acquired in the community may be either CA-MRSA or HA-MRSA
n Incorrect diagnosis (table 7).                                                                                                                                                                      with antibiotics and surgi-
                                    n CA-MRSA infections have been associated with fulminant infection and death
n A purulent collection that                                                                                                                                    Recurrent cellulitis                  cal debridement.
                                    n Clindamycin should be the first-choice antibiotic for suspected CA-MRSA infections
  requires drainage.                                                                                                                                            Recurrent cellulitis occurs in      n Relief of pressure on foot
                                    n HA-MRSA infections that require oral therapy are usually treated with the combination of rifampicin
n Underlying osteomyelitis or                                                                                                                                   20% of patients, especially in        ulcers.
  foreign body requiring sur-         plus fusidic acid                                                                                                         those with lymphoedema.                Microbiological swabs are
                                    n Resistance in MRSA to rifampicin and fusidic acid rapidly emerges if monotherapy (with either
  gical intervention.                                                                                                                                           Support stockings (compres-         usually not helpful in estab-
n Inappropriate antimicrobial         rifampicin or fusidic acid) is given                                                                                      sion stockings) have been           lishing the diagnosis. Infec-
  choice, including an unusual      *(Adapted from Therapeutic Guidelines: Antibiotic.1 Also refer to your regular pathology provider for                       shown to reduce or, in some         tions are generally polymi-
  exposure and/or unusual           antibiograms, as geographical variations in susceptibility patterns occur.)                                                 cases, eliminate recurrences.       crobial and should be treated
  organism.                                                                                                                                                     They should be fitted under         with broad-spectrum antibi-
n Inadequate drug levels (usu-     common complication),                      improvement is not adequate.                                                      medical supervision, as they        otics (either in combination
                                                                                                                            Table 7: Examples of
  ally due to non-compliance).     anaemia and neutropenia.                   A pre-existing dermatological                                                     may be harmful if significant       or as a single agent such as
                                   These usually occur after                  condition (for example, tinea                                                     peripheral vascular disease is      amoxycillin-clavulanate). All
                                                                                                                             conditions that can
Infection with MRSA                more than two weeks on ther-               pedis) may be the portal of                                                       present.                            chosen antimicrobial agents
                                                                                                                               mimic cellulitis
The most common oral ther-         apy and are reversible after               entry and also require treat-                                                        Good skin care is essen-         should always cover S
apy for MRSA infection is          stopping treatment.                        ment to prevent recurrence.               n   Acute gout                          tial, with treatment of any         aureus.
combination rifampicin and                                                       Since the implementation of            n   Arthritis (inflammatory)            underlying eczema or dry               Potentially limb- or life-
fusidic acid. It is extremely      Other aspects of treatment                 Haemophilus influenzae type               n   Bursitis (inflammatory)             and cracked skin.                   threatening infections should
important to ensure that the       Ancillary measures (such as                B (Hib) vaccination, the most                                                        Foot care is important in        be referred promptly for spe-
                                                                                                                        n   DVT
drugs are continued in com-        leg elevation and immobilisa-              common cause of facial                                                            patients with recurrent leg cel-    cialist assessment and treat-
bination at all times, as          tion) to reduce swelling and               erysipelas in adults and chil-            n   Erythema nodosum                    lulitis. They should be             ment.
monotherapy with either            relieve pain are important and             dren is S pyogenes. Other                 n   Fixed drug eruption                 instructed to carefully dry            The most crucial aspect in
agent can lead to emergence        often underestimated — a                   organisms can be causative,               n   Insect bite                         between the toes to minimise        patients with diabetes is deter-
of resistance in MRSA strains      possible reason for some cases             and underlying dental and                                                         tinea pedis-related recurrences.    mining the presence of bone
                                                                                                                        n   Malignancy
within periods as short as 24-     responding better to therapy               sinus infection should also be                                                       Topical antifungals are usu-     infection, because osteo-
48 hours.                          in hospital than in the com-               excluded.                                 n   Neutrophilic dermatoses             ally adequate treatment but         myelitis modifies treatment
   It is not uncommon for          munity.                                                                                  (eg, Sweet’s syndrome)              can cause contact dermatitis,       options. Probing the ulcer to
patients to run out of                In all patients with diabetes,          Differential diagnoses                    n   Panniculitis                        usually indicated by apparent       bone is a cheap, simple and
rifampicin because, unlike         good glycaemic control assists             The differential diagnosis of             n   Pyoderma gangrenosum                worsening of symptoms. A            well-tolerated bedside test to
fusidic acid, it is not obtain-    healing and resolution of                  cellulitis includes other der-                                                    combination of topical anti-        detect osteomyelitis.
                                                                                                                        n   Vasculitis
able on an authority prescrip-     infection. Frequent dressing of            matological conditions in                                                         fungal and corticosteroid may          A positive test has an 89%
tion for the treatment of          ulcers or open areas (with the             which inflammation is promi-                                                      overcome this problem.              likelihood for the presence of
MRSA infections.                   help of home nursing and                   nent. This should always be                                                          Older remedies such as foot      bone infection but the nega-
   If the patient runs out of,     Hospital in the Home) may                  considered in unusual presen-                                                     soaks in a solution of potas-       tive predictive value of the test
or is intolerant to, either        aid prevention of secondary                tations and/or poor response                                                      sium permanganate (Condy’s          is only 56%. So a positive test
rifampicin or fusidic acid,        infections.                                to treatment (see table 7).                                                       crystals) can also help resolve     is highly suggestive of
both drugs should be stopped          Initial treatment should                   Conditions such as a fixed                                                     some cases, but occasionally        osteomyelitis but a negative
simultaneously, and expert         cover streptococci and S                   drug eruption, insect bite,                                                       oral antifungal therapy is          test (the presence of a superfi-
advice sought. Linezolid,          aureus. Spontaneous onset of               acute gout, DVT and pyo-                                                          required.                           cial ulcer only) does not
available in hospitals, has        lower-limb erysipelas in a                 derma gangrenosum may                                                                Prophylactic antibiotics are     exclude bone infection.
useful activity against MRSA       non-diabetic patient or in a               coexist with infection and                                                        occasionally used in patients          When deep infection
but is extremely expensive and     patient with lymphoedema                   complicate diagnosis and                                                          with recurrent cellulitis but, in   cannot be conclusively elim-
has an adverse-event profile       (congenital or after surgery               management.                                                                       appropriate patients with fre-      inated or the patient has
that may restrict use.             and lymph node dissection) is                 Bursitis and septic arthritis                                                  quent attacks, early patient        non-healing ulcers, especially
   Routine blood monitoring        almost always streptococcal.               may cause erythema of the                                                         initiation of antibiotics when      after two weeks of antibiotic
of patients taking linezolid is       Initial treatment with benzyl           overlying skin: these condi-                                                      symptoms start may be a             therapy, further tests are
essential to detect any haema-     penicillin is acceptable but a             tions must always be excluded                                                     better option.                      usually required. These
tological toxicity such as         staphylococcal or other cause              when cellulitis overlies a joint                                                     Antibiotics for prophylaxis      include X-rays, bone scans
thrombocytopenia (the most         should be considered if                    or bursa, as treatment usually                                                    should have a favourable                           cont’d next page

                                                                                                                                                     16 September 2005 | Australian Doctor |   29
 How to treat – skin and soft tissue infections

 from previous page                                                                                          on the various tissue planes         pain in the affected area           the desquamation is often
 and/or MRI or CT scans.                                                                                     involved.                            despite modest overlying skin       only evident in the convales-
    It is important to remem-                                                                                   The feature common to all         changes. These early changes        cent period, permitting only
 ber that interpreting X-rays                                                                                is the need for aggressive           rapidly progress to fascial         retrospective diagnosis in
 of diabetic feet can be prob-                                                                               surgical management with             and skin necrosis.                  many cases, if the patient sur-
 lematic, especially when neu-                                                                               debridement, as well as early           Clostridial myonecrosis (gas     vives.
 ropathic bone changes are                                                                                   recognition, because of the          gangrene) is caused by                 While there are obviously
 prominent. Therefore, in                                                                                    high mortality rate.                 clostridial contamination of a      genetic predispositions to the
 patients with diabetic ulcers,                                                                                 Factors that may suggest a        wound that contains devi-           development of this syn-
 specialist advice should be                                                                                 complicated infection arising        talised tissue.                     drome, the critical require-
 sought if uncertainty remains                                                                               from a simple skin or soft              This infection is charac-        ment is infection with a toxin-
 about deep infection.                                                                                       tissue infection include:            terised by a short incubation       producing strain. The presence
    Not all patients with dia-                                                                               n Pain at the site, out of pro-      period, a foul-smelling dis-        of such strains is not revealed
 betes and foot ulcers require                                                                                 portion to cellulitis.             charge and crepitus within the      by standard laboratory tests.
 antibiotics. For ulcers without     Pyoderma with surrounding erythema. Both S pyogenes and                 n Hypo-aesthesia at the site of      tissue planes.                      Specialist laboratory advice
 signs of infection, improving       S aureus were isolated from a swab of the lesion.                         cellulitis.                           All patients who may have        about additional tests should
 glycaemic control and encour-                                                                               n Prominent systemic signs.          a deep infection should be          be sought.
 aging non-weight bearing may        infections. Regular review by                                           n Contaminated wound or              referred to hospital as soon           Although a preceding skin
 be sufficient.                      a skilled podiatrist, who                                                 cut.                               as possible, as death may be        lesion may be present (or have
    For small ulcers with            understands the vascular,                                               n Skin necrosis.                     inevitable with late presen-        been present), the clinical syn-
 localised skin involvement,         neuropathic and associated                                              n Foul-smelling discharge or         tation, irrespective of treat-      drome is usually indistin-
 oral amoxycillin-clavulanate        features of diabetic foot con-                                            gas bubbles in the discharge.      ment.                               guishable from the toxic
 (875mg-125mg) bd for 10-            ditions, is essential.                                                  n Gas in the tissues (crepitus                                           shock syndrome associated
 14 days can be added. Alter-           Many hospitals provide an                                              clinically or gas on X-rays).      Toxin-mediated skin                 with tampon use.
 natives include cephalexin          outpatient high-risk foot clinic                                           Risk factors for necrotising      conditions                             These patients should be
 500mg qid plus metronida-           — another useful resource.                                              fasciitis include:                   These infections are caused by      transferred to hospital
 zole 400mg bd/tid or, for           Well-fitting protective foot-                                           n Obesity.                           super-antigen toxins produced       urgently, because they gener-
 beta-lactam-allergic patients,      wear and education on foot                                              n Diabetes.                          by S aureus or S pyogenes.          ally require supportive ther-
 ciprofloxacin 500mg bd plus         care is essential, as the three-                                        n Alcoholism.                        Affected patients present with      apy as well as antibiotics.
 clindamycin 300mg qid.              year recurrence rate (and asso-                                         n IV drug use.                       a cluster of clinical signs char-      Clindamycin added to
    More serious infection           ciated mortality rates) can be     Non-healing skin lesions in an          The most common sites are         acterised by an exaggerated         penicillin is an essential com-
 should be referred and inves-       about 20%.                         immunocompromised patient            the legs, abdominal wall and         immune response with                ponent of therapy in strep-
 tigated as discussed earlier. All                                      from which M chelonae was            perineal areas. Type I infec-        pyrexia, hypotension, con-          tococcal toxic shock syn-
                                                                        isolated on biopsy culture.
 patients should have non-           Deep complicated skin and          Histopathology demonstrated
                                                                                                             tion, also known as synergistic      junctival injection and a gen-      drome, as it has been shown
 invasive vascular studies.          soft tissue infections             suppurating granulomata and          gangrene, is usually polymi-         eralised, often fine, macular       to reduce toxin production
    It is crucial that all risk      The terminology describing         organisms on acid-fast stains.       crobial, while type II is caused     or maculopapular rash.              and there are data that indi-
 factors are aggressively mod-       deep complicated infections is     Resolution required a                by S pyogenes.                          The palms and soles are          cate penicillin treatment
 ified to aid prevention and         confusing, as multiple clinical    prolonged course of quadruple           There is usually profound         often affected and may              alone is probably inadequate
 treatment of diabetic foot          syndromes exist, depending         antibiotic therapy.                  systemic toxicity and severe         desquamate. Unfortunately,          in fulminant cases.

     Conclusion                                                                                                                                                                        References
                                                                                                                                                                                       1. Writing group for
 SKIN and soft tissue infections are           ■ Taking a history of the injury or        ■ Review of response to therapy.               terns, is important to optimise ther-         Therapeutic Guidelines:
 the most common bacterial infec-                events preceding the onset of the        ■ Follow-up recommendations, includ-           apy. If there is concern about the            Antibiotic. Therapeutic
 tions in humans. Essential manage-              infection.                                 ing management of underlying dis-            severity of the infection, a phone call       Guidelines: Antibiotic.
 ment principles of these infections           ■ Physical examination to determine          orders and guidelines for prevention.        or referral to the local hospital may         Version 12. Therapeutic
 include:                                        the extent of infection and any asso-       Knowledge of antibiotic choices,            be prudent, where formal admission            Guidelines Ltd, Melbourne,
 ■ Checking patient history for predis-          ciated clinical clues to guide diag-     guided by the nature of the infection          for therapy or Hospital in the Home           2003.
   posing and underlying conditions.             nosis and empirical treatment.           and local antibiotic susceptibility pat-       facilities may be accessed.                   2. NHMRC. Australian
                                                                                                                                                                                       Immunisation Handbook.
                                                                                                                                                                                       NHMRC, Canberra, 2003.

                                                                                                                                                                                       Further reading
     Authors’ case studies                                                                                                                                                             Gilbert DN, et al (eds).
                                                                                                                                                                                       The Sanford Guide to
 An ulcerated foot injury in            The ulcer eventually healed                                                                               hospital for assessment and          Antimicrobial Therapy.
 a patient with diabetes             after two months.                                                                                            probable IV antibiotics.             Antimicrobial Therapy Inc,
 A 53-YEAR-old man pre-                                                                                                                                                                Vermont, US, 2005.
 sented to the high-risk foot        Comment                                                                                                      Comment                              Eron LJ, et al. Managing
 clinic after a laceration to the    Diabetic foot infections are                                                                                 This is a CA-MRSA infec-             skin and soft tissue
 plantar surface of his foot         common. Probing to bone is                                                                                   tion in a known at-risk indi-        infections: expert panel
 while gardening barefoot. He        the best bedside test for                                                                                    vidual (football player). It is      recommendations on key
 had severe bilateral peripheral     osteomyelitis. Empirical                                                                                     important to be aware of ful-        decision points. Journal of
 neuropathy secondary to long-       antibiotic choice should be                                                                                  minant syndromes and to              Antimicrobial Chemotherapy
 standing poorly controlled          broad spectrum, as diabetic                                                                                  determine early whether to           2003; 52:(Suppl.S1);i3-i17.
 diabetes.                           foot infections tend to be                                                                                   hospitalise Tom.                     Gottlieb T, et al. Soft tissue,
    The small laceration had         polymicrobial.                                                                                                  Clindamycin can be used           bone and joint infections.
 increased in size to a 2-3cm                                                                                                                     as first-choice therapy, espe-       Medical Journal of Australia
 ulcer. There were no systemic       Abscesses resistant                   Tom also feels unwell,            still has a temperature              cially since the strain is also      2002; 176:609-15.
 signs of infection or local cel-    to cephalexin and                  with fever (38.5°C) and              (38°C) and the axillary              susceptible to erythromycin.         Swartz MN. Cellulitis.
 lulitis and the ulcer did not       flucloxacillin                     night sweats of 1-2 days’            lesion is now ‘pointing’.            If the CA-MRSA strain had            New England Journal of
 probe to bone.                      TOM is a 19-year-old uni-          duration. The lesion in the             Incision and drainage yields      been susceptible to clin-            Medicine 2004; 350:904-12.
    Initial blood investigations     versity student who plays          axilla does not have any             20mL of thick pus, sent for          damycin but resistant to ery-        Falagas ME. Narrative
 revealed a normal neutrophil        football on the weekends. He       obvious site for collecting a        microbiology. The next               thromycin, and he had failed         review: diseases that
 count and a raised C-reactive       presents with his third episode    specimen for culture.                evening Tom phones to say            to improve on clindamycin,           masquerade as infectious
 protein. A swab from the            of “boils” in the past six            A swab is collected from          the axillary lesion is only          an alternative to it may have        cellulitis. Annals of Internal
 ulcer grew “mixed flora”            months. He has required inci-      the thigh lesion. Previous           slightly better and the thigh        been required. He may have           Medicine 2005; 142:47-55.
 (Gram-positive and Gram-            sion and drainage of lesions       blood tests (fasting blood           lesion is worse. He reports          needed IV vancomycin fol-
 negative aerobic organisms).        on one occasion and usually        glucose, FBC) were normal            that he “still feels like he has a   lowed by oral therapy with           Online resources
    The patient was started on       takes oral cephalexin or flu-      and were not repeated.               fever” and had night sweats          rifampicin and fusidic acid          n
 oral amoxycillin-clavulanate        cloxacillin.                          Tom is treated with flu-          last night.                          (see page 28 for further dis-
 (875mg-125mg) bd for 10-14             Swabs for microbiology          cloxacillin orally, 1g every six        The swab result from the          cussion).                            n HealthInsite:

 days, with frequent review          have never been collected. The     hours, and advised that he is        thigh shows a S aureus vari-            Check for chronic or      
 and dressings at the clinic.        boils are usually on his thighs,   likely to need the axillary          ant susceptible to clin-             underlying skin conditions           n DermNet NZ:

 The importance of foot care         buttocks and arms, but this        lesion incised and drained if it     damycin and erythromycin             and implement the ‘recurrent 
 was stressed and he was told        time he has a very red, tender     does not improve.                    but resistant to flucloxacillin      staphylococcal infection’ pro-
 to wear shoes at all times,         5cm lump in his axilla and a          The next day Tom reports          and cephalexin. The same             tocol. Counsel Tom about
 especially outside the house,       smaller lesion on the inner        he still feels unwell and has        strain is also isolated from         behaviour that may encour-
 given his significant periph-       thigh that he has squeezed to      become nauseated since               the pus obtained at drainage.        age transmission of infection,
 eral neuropathy.                    express some pus.                  starting flucloxacillin. He          Tom is referred to his local         such as sharing towels.

30   | Australian Doctor | 16 September 2005                                        
 How to treat – skin and soft tissue infections

     GP’s contribution
                                                                dry them with a hairdryer.                                                                                                           Extremely unlikely, if ever.                                  General questions for the                    Should all ulcers in patients
                                                                   The nasal infection subsided                                                                                                   Being a ‘coagulase-negative’                                     authors                                      with diabetes be “probed to
                                                                but the facial folliculitis per-                                                                                                  staphylococcus, the organism                                     The incidence of CA-MRSA                     the bone” to detect
                                                                sisted, so I changed the antibi-                                                                                                  could have been labelled as                                      infection is increasing. It is               osteomyelitis and should all
                                                                otic to Minomycin. It still did                                                                                                   S epidermidis (S aureus yields                                   suggested that both swabs and                these patients have bone scans
                                                                not settle and I referred him                                                                                                     a positive coagulase test).                                      biopsies be taken. For the                   if not responding to treatment
                                                                to a dermatologist, who rec-                                                                                                      Not all coagulase-negative                                       latter, is a formalin-soaked                 within, say, one month?
                                                                ommended a tea-tree oil shav-                                                                                                     staphylococcal species are S                                     specimen adequate?                              Part of the inspection of
                                                                ing cream, Retin-A gel, and                                                                                                       epidermidis.                                                        Swabs from lesions or spec-               anything other than the most
               Lugarno, NSW
                                                                shaving in a downward direc-                                                                                                         Others include S schleiferi,                                  imens of pus in sterile con-                 superficial diabetic foot ulcers
                                                                tion only.                                                       intolerance/coeliac disease and                                  S lugdunensis, S simulans and                                    tainers for CA-MRSA isola-                   is to see if they can be probed
 Case study                                                        The folliculitis persisted,                                   skin infections?                                                 many more, which can be                                          tion are adequate in virtually               to bone. If the patient has not
 MR SP, 49, had a long his-                                     and a second dermatologist                                          Atopic individuals are prob-                                  more pathogenic than S epi-                                      all situations. Biopsies are                 improved after, say one
 tory of allergic rhinosinusitis,                               restarted Eryacne gel and a                                      ably at increased risk of skin                                   dermidis in certain situations                                   required for skin and soft                   month of treatment, complete
 a rhinoplasty in 1990, gout,                                   glycolic acid lotion twice                                       infections (of which folliculitis                                (this case scenario is probably                                  tissue infections in which                   reassessment is required.
 recently-diagnosed gluten                                      daily. Minomycin was later                                       is one) by virtue of xero-                                       not one of those).                                               unusual organisms (usually                      This includes a repeat
 intolerance, with raised                                       restarted, without benefit.                                      derma, but definitely if they                                       Additionally, some S                                          mycobacteria, fungi, parasites,              probe and checking the
 antigliadin antibodies, and                                       Mr SP saw a third derma-                                      have any chronic skin condi-                                     aureus strains have false-                                       etc) or non-infective condi-                 microbiology, radiology and
 olecranon bursitis.                                            tologist in June 2005, who                                       tion such as eczema or other                                     negative coagulase tests                                         tions are suspected.                         compliance with all aspects
   I saw him in 2002 with an                                    diagnosed aberrant hair                                          dermatitis.                                                      (which relate to incomplete                                         These specimens require                   of therapy — not just the
 acneiform eruption involving                                   growth with secondary infec-                                        There is no association                                       testing).                                                        division (or separate punch                  antibiotics.
 the shaving areas of his face.                                 tion due to over-elastic skin.                                   between gluten intolerance or                                       In general, most truly                                        biopsies can be collected), with                Resorting to bone scans
 He had developed this six                                      His suggestion was to destroy                                    coeliac disease and skin infec-                                  coagulase-negative staphylo-                                     one piece (or punch biopsy)                  and CT/MRI without consid-
 months earlier while in the                                    the abnormal follicles with a                                    tions. However, there is a spe-                                  coccal strains are only path-                                    going into formalin, and the                 ering the clinical and labora-
 Middle East.                                                   laser and that SP use an elec-                                   cific blistering skin condition                                  ogenic in the presence of                                        other into a sterile container               tory factors and the simple
   It looked like a low-grade                                   tric razor — so that any pro-                                    associated with the above con-                                   prosthetic devices and signif-                                   (usually onto sterile gauze                  plain X-rays is ill-advised.
 folliculitis, so I suggested he                                truding hairs could be                                           ditions — dermatitis herpeti-                                    icant immunosuppression.                                         lightly soaked, not ‘swim-                   Interpretation of imaging
 use Sebamed liquid face wash                                   plucked. SP has just started a                                   formis.                                                             Usually laboratories will                                     ming’, in sterile normal saline).            studies (including plain X-
 for shaving, and topical Ery-                                  long course of laser follicular                                                                                                   not identify staphylococcal                                         There is no more certain                  rays) in diabetic foot infec-
 acne. The infection persisted,                                 destruction.                                                     Skin swabs did not reveal                                        isolates beyond determining                                      way to upset a microbiologist                tions can be difficult.
 so I added oral doxycycline.                                                                                                    any pathogenic organism.                                         whether they are coagulase                                       than to put a specimen in for-                  Specialist review, including
   Later a nasal swab showed                                    Questions for the authors                                        Could the nasal Staphylo-                                        negative or positive, unless a                                   malin and then call for the cul-             discussion of the usefulness of
 Staphylococcus epidermidis,                                    Is there an increased risk of                                    coccus epidermidis have                                          special clinical reason exists                                   ture result. Formalin kills most             imaging with the radiologist
 which was treated with oral                                    folliculitis in patients with                                    been the trigger for the                                         for doing so (for example, iso-                                  things, apart from prions, so                and nuclear medicine special-
 Keflex and intranasal Chlorsig                                 childhood allergic diatheses,                                    chronic folliculitis? Can this                                   late from blood culture or                                       if in doubt call the laboratory              ist, is recommended in
 ointment, and I suggested he                                   ie, eczema/sinusitis? Is there a                                 ever be a pathogen in an oth-                                    operative specimen from                                          microbiologist for advice                    patients not responding to
 keep his fingernails short and                                 relationship between gluten                                      erwise healthy individual?                                       prosthetic joint or tissue).                                     before collecting the specimen.              treatment.

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 1. David, 7, attends with his mother. He has                                                     Which TWO management decisions are                                                              ❏ a) Family and close contacts should also be                                               8. You decide that a trial of oral antibiotics
 large, bullous, crusting sores around his                                                        most appropriate?                                                                                 treated for carriage of staphylococcus                                                    is reasonable. Phyllis is afebrile. Which
 mouth, which you diagnose as impetigo.                                                           ❏ a) A swab should be taken before starting                                                     ❏ b) You order an FBC and a fasting blood                                                   TWO actions are most appropriate?
 Which ONE statement about impetigo is                                                              treatment                                                                                       glucose level, looking for underlying disease                                             ❏ a) Take blood cultures
 correct?                                                                                         ❏ b) Hot packs, incision and drainage are the                                                   ❏ c) You suggest oral and topical antibiotics                                               ❏ b) Swab the lesion
 ❏ a) Streptococcus pyogenes is the principal                                                       treatment of choice                                                                           ❏ d) You give Colin the choice of antibiotics or                                            ❏ c) Start penicillin and dicloxacillin
    cause of impetigo                                                                             ❏ c) Antibiotics are usually given because they                                                   more extensive hygiene measures                                                           ❏ d) Encourage elevation of the leg
 ❏ b) It is important to swab the lesion to                                                         shorten the duration of the infection
    identify the organism                                                                         ❏ d) Assessment of any risk factors that                                                        6. Phyllis, 65, presents with a red and                                                     9. Which ONE of the following statements
 ❏ c) The appearance of the lesions suggests                                                        predispose to the development of furuncles                                                    swollen left leg. Which THREE clinical                                                      about diabetic ulcers is correct?
    Staphylococcus aureus as the causative                                                                                                                                                        features are most consistent with a                                                         ❏ a) Up to one-quarter of patients with
    organism                                                                                      4. He returns a week later, because the                                                         diagnosis of cellulitis?                                                                       diabetes develop foot ulcers
 ❏ d) David can attend school as long as                                                          lesion has increased in size and is                                                             ❏ a) The leg is painful                                                                     ❏ b) Microbiological swabs are mandatory
    treatment has started                                                                         extremely tender. He is systemically well.                                                      ❏ b) The border of the erythema is ill-defined                                                 to accurately define the infecting
                                                                                                  Which TWO options are correct in the                                                            ❏ c) The patient is systemically well and                                                      organism
 2. Which TWO management strategies                                                               ongoing management of Colin?                                                                       afebrile                                                                                 ❏ c) Osteomyelitis does not develop while
 would you recommend for David?                                                                   ❏ a) A swab of the lesion is indicated                                                          ❏ d) Her left inguinal lymph nodes are                                                         ulcers are superficial
 ❏ a) Flucloxacillin is the treatment of                                                          ❏ b) Further incision and drainage is warranted                                                    palpable                                                                                 ❏ d) All patients with diabetes and foot ulcers
    choice                                                                                           if the lesion is pointing                                                                                                                                                                   require antibiotics
 ❏ b) Crusts should be removed twice daily                                                        ❏ c) Clindamycin should be started                                                              7. Which TWO clinical features would
 ❏ c) Topical mupirocin is contraindicated                                                           empirically                                                                                  indicate that Phyllis would be best managed                                                 10. Which ONE feature does not place a
    because of problems with resistance                                                           ❏ d) Povidone-iodine body washes should be                                                      in hospital?                                                                                wound at high risk of infection?
 ❏ d) If lesions continue to appear, swabs are                                                       started immediately                                                                          ❏ a) Tachycardia and hypotension                                                            ❏ a) The injury occurred less than eight
    indicated                                                                                                                                                                                     ❏ b) Chronic venous hypertension                                                               hours ago
                                                                                                  5. Colin recovers but returns twice in the                                                      ❏ c) The erythema is limited to the area                                                    ❏ b) Potential involvement of a joint
 3. Colin, 30, is a corporal in the army.                                                         next month with two smaller but similar                                                            overlying the medial malleolus                                                           ❏ c) A history of immunosuppression
 He presents with a furuncle on his left                                                          lesions. You provisionally diagnose                                                             ❏ d) She is able to bear her weight and walk                                                ❏ d) The wound is a puncture wound
 buttock but is otherwise well. He has a                                                          staphylococcal carriage. Choose the TWO                                                            without pain
 BMI of 28 and plays rugby regularly.                                                             most suitable management options.


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                                                                                                                                                                                                                                                                                              HOW TO TREAT Editor: Dr Lynn Buglar
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     NEXT WEEK How to Treat explores the ubiquitous problem of muscle pain and weakness. The author is Associate Professor Norm Broadhurst, department of orthopaedics, Flinders University, Bedford
     Park; senior visiting medical specialist, rehabilitation, Queen Elizabeth Hospital, Woodville; and in private practice in Glenelg, SA.

32     | Australian Doctor | 16 September 2005                                                                                                               

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