Zitelli - Comparative Dermatology outline

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					                                                                Basil J. Zitelli, M.D.
                                                                Children’s Hospital of Pittsburgh

         COMPARATIVE DERMATOLOGY                                                             NOTES

I.   Eczema
     A. Distribution
     B. Infantile
        1.    Facial
        2.    Truncal
        3. For such a common problem that has been described since the 19th
          century, Hill and Sultzberger in 1935 characterized it as a clinical entity.
          a. 7/1000 in the US, 3%-5% of children from 6 mo to 10 yr
          b. Acute (erythema, scaly, vesicle, crusts)
              Chronic (scaly, lichenified, pigment changes)
          c. Infancy - initially red, pruritic papules/plaques, diaper area usually
          d. Childhood - circumscribed erythematous scaly lichenified plaques,
              frequent secondary infection
        4.    Pruritus, irritability are common associated symptoms
        5.    Scabies - intensely pruritic, irritable, can be diffuse and more papular
          a. Sarcoptes scabiei infestation: female mite burrows and lays eggs
              resulting in burrows, may involve genital area, palms and soles
        6.    Wiskott Aldrich - X-linked recessive, recurrent infections that begin in
          a. Inability to form antibody to bacterial polysaccharide antigens is the
              most common immune defect, but some patients may have a partial
              T-cell defect as well.
     C. Childhood - usually begins between 4y-10y
        1.     Dry, scaly, pruritic, localized to wrists, ankles, antecubital and
          popliteal fossae; May involve the hands with cracking, drying and
          scaling of palmar surface and excoriations and lichenification of the
          dorsum of hand
        2.    Nummular eczematous dermatitis - discrete coin shaped red patches
          in patients with eczema, beginning as tiny papules and vesicles forming
          confluent patches, pruritic. with lack of central clearing
          a. Psoriasis - red , demarcated plaques with dry silvery scale tend to be
              located on extensor surfaces of extremities, scalp and buttocks.
              In infants may present as diaper dermatitis
              (1) Thickened skin produced by increased epidermal growth, there
                are areas of thin skin between epidermal layers with scale close to
                surface of skin; scale removed results in bleeding point called
                Auspitz sign - hallmark of psoriasis.

            (2) Skin of palms may be markedly thickened with silvery fissuring
             of palmar creases
         b. Tinea corporis - infection of the glabrous (non hairy) skin; pruritic,
            annular lesion with central clearing and active vesicular border.
            (1) Differentiate from atopic dermatitis because of its propensity to
             autoinoculate and central clearing.

II. Seborrhea - red scaly eruption occurring primarily on hair-bearing and
       intertriginous areas: scalp, eyebrow, eyelashes, perinasal, presternal,
       postauricular area and intertriginous areas. Pityrosporum and Candida
       have been implicated as causative agents
    A. Greasy, salmon-colored scaly dermatitis, usually pruritic
    B. Differentiate form histiocytosis X and T. Corporis
       1.     Histiocytosis X - proliferative disorder of Langerhans type cells with
         specific cytological markers. Skin infiltration is most common in Letterer-
         Siwe disease, beginning as diffuse, papular scaly eruption; differs from
         seborrheic dermatitis by infiltrated crusted petechial rash, frequently
         involving the trunk, associated with chronic ear infection, draining ears
         and hepatosplenomegaly.

I.   Tinea corporis - found in any age group, usually acquired from an infected
        domestic animal (Microsporum canis) or by direct human contact
        (Trichophyton, Microsporum , and Epidermophyton species)
     A. Differentiate from granuloma annulare
        1.    Depth of lesion - dermal infiltration of lymphocytes around altered
         collagen, epidermis is normal, may have slight erythema
        2.    Begins as nodule or papule, gradually extending peripherally to form
         a ring, found commonly on extensor surfaces of lower legs, feet, fingers,
         hands .
        3. Usually asymptomatic and resolves spontaneously within a few
         months to years.
     B. Differentiate from pityriasis rosea, herald patch
        1. Self-limited disorder which can occur at any age but more often
        2. adolescents and young adults.
        3. Eruption begins with a herald patch - large oval lesion slightly scaly
         sometimes with central clearing.
        4. Prodrome of malaise, headache and mild constitutional features may
         precede the rash.
        5. 5-10 days later smaller lesions appear on the trunk , papules to ovals
         with scale, creating AChristmas tree@ pattern.
        6. Rash peaks in several weeks and fades over 4-6 weeks


       7. Consider secondary syphilis rash which may be a truncal scaly rash in
        Christmas -tree distribution, but may involve the hands and feet.
    C. And while we are talking about palmar rashes ...
       1. Measles - close to being eradicated in the U.S. ; about 100 cases in
        the U.S. last year, most imported
        a. Cough, conjunctivitis, coryza
        b. Rash preceded by Koplik spots
        c. Rash begins in hairline and spreads cephalocaudally
        d. Palms/soles involved
       2. Drug eruption - many different types, morbilliform accounting for more
        than half
        a. Erythematous macules and papules begin to erupt on face and trunk
             5- 14 days after initiation of a drug and spreads to the extremities
             over several days; may involve palms and soles

II. Urticaria
    A. Transient, well-demarcated wheals, usually pruritic, often as part of an
       acute, IgE-mediated hypersensitivity reaction. May occur anywhere and
       any size; may leave central clearing leading to annular, polycyclic and
       arcuate plaques.
       1. Acute urticaria - <6 wks, triggered by hypersensitivity to foods, drugs,
         insect bites, contact antigens, infection (strep, hepatitis) or inhaled
       2. Physical agents: cold, heat, water, exercise, or mechanical pressure.
       3. Dermatographism is common
    B. Differentiate:
       1. Hereditary angioedema - angioedema differs from urticaria by involving
         deeper layers of the skin including subcutaneous tissues
         a. H. A. - autosomal dominant C1 inhibitor deficiency involving lips,
              tongue and airway, lacks urticaria, recurrent GI colic
       2. Mastocytosis - collection of mast cells that release histamine when
         stimulated causing wheal and flare reaction.
         a. May have numerous brownish plaques in the skin and GI involvement -
              urticaria pigmentosa
       3. Erythema marginatum - not pruritic
         a. Gyrate urticarial plaques formed by coalescence of individual pruritic
              urticarial lesions that may mimic erythema marginatum
       4. Urticarial / erythema multiforme-like reaction
         a. Constellation of urticarial lesions, periarticular swelling, extremity
              angioedema - usually in association with upper respiratory tract
              infection, sulfa-containing antibiotics, or cefaclor
         b. Lesions nonpruritic or mildly pruritic creating target or gyrate shapes
              but no vesiculation, migratory stocking/ glove angioedema which is

            painful (suggesting hypersensitivity type III reaction rather than
          type I )
      5. Erythema multiforme (EM) - reactive erythema with symmetrical
           distribution, dorsum of hands and feet, palms and soles.
       a. Dusky red macules or erythematous wheals evolving into target -
            shaped lesions may simulate urticaria but less pruritic
       b. May vesiculate or become bullous
      6. Stevens - Johnson syndrome (SJS)
       a. Rarely EM may progress to SJS with mucus membrane and epidermal
            necrosis and shedding
       b. Constitutional features of fever, cough, sore throat, vomiting, diarrhea,
            chest pain and arthralgias are common
       c. Vesiculation and bullae appear early, along with mucus membrane
            involvement of oral cavity conjunctivae, and genital mucus
       d. Toxic epidermal necrolysis - (TEN) may be the most fulminant form of
            (1) Similar inciting agents as SJS
            (2) Begins as generalized erythroderma followed by sloughing of the
              skin and mucus membrane involvement
            (3) Nikolsky sign indicating epidermal layer cleavage (epidermal-
              dermal junction, differing from cleavage plane in staphylococcal
              scalded skin syndrome which is between the upper and mid

III. Vascular tumors and malformations
     A. Vascular anomalies - 2 types
        1. Hemangiomas - benign tumors characterized by rapid proliferative
          phase lasting 8 -10 months with slow involution over several years,
          comprised of proliferating endothelial cells
          a. 1% of newborns may have hemangiomas and up to 10% of children
               under 1 yr of age - most appearing by 4 weeks of age
        2. Vascular malformations are dysplastic vessels without endothelial
          proliferation, subdivided into vessel type ( capillary, venous, arterial,
          lymphatic or combination) and flow (high flow or low flow)
          a. Salmon patches occur in 60-70% of newborns usually at nape of neck,
               glabella, forehead or upper eyelids.
          b. At birth 0.2-0.3% of children have port wine stains (PWS) which tend
               to persist.
     B. Hemangiomas - alteration in balance of endothelial cell proliferation and
        inhibitors of vascular growth.

      1. Proliferative stage - high levels of basic fibroblast growth factors,
       vascular endothelial growth factors and a variety of other stimulators of
       vascular growth
      2. Involuting hemangiomas exhibit tissue inhibitor metalloproteinase and
       mast cells, interferon alpha (2α and 2β), thalidomide, angiostatin and
       other inhibitors of angiogenesis.
      3. Natural history of hemangiomas in non-vital areas is spontaneous
       involution: 25% by 2 yr, 40-50% by 4 yr, 60 -75% by 6 yr, 95% by
        a. RICH (rapidly involuting congenital hemangioma), NICH (non-
       involuting congenital hemangioma)
      4. Extensive facial hemangiomas raise suspicion associated anomalies
       and other tissue involvement.
       a. PHACES - Posterior fossa malformations, large Hemangiomas of the
            face, Arterial abnormalities, Coarctation of the aorta and Cardiac
            defects, and Eye abnormalities, Sternal abnormalities
       b. Hemangiomas of the cervicofacial areas may also involve the airway,
            especially with a beard distribution, presenting with biphasic stridor,
            normal voice and no swallowing difficulties.
            (1) Scoring system = 1 point for each: left preauricular area, right
              preauricular area, chin, lower lip, anterior neck.
              (a)     4 points = 63% chance of symptomatic airway involvement
       c. Extensive craniofacial hemangiomas may be associated with
            anomalies of cerebral arteries and aortic arch, orbital and periorbital
      5. Treatment - many modalities including:
       a. Flashlamp pulsed dye laser, topical and systemic steroids, intralesional
            steroid injections, embolization and excision
       b. Propranolol
       c. Experimental modalities - thalidomide, COX2 inhibitors, doxycycline,
            metalloproteinase inhibitors, angiostatin
   C. Vascular malformations - port wine stains (PWS) persist unchanged
      during childhood, tend to darken in adolescence and adulthood
      1. Sturge-Weber syndrome - PWS at birth involving V1, may have
       ipsilateral leptomeningeal vascular malformations and ophthalmic
       involvement with choroid angioma and glaucoma.
       a. Occurs in about 10% of patients with V1 PWS manifesting by 1 yr of
            age with seizures
      2. Treatment with flashlamp pulsed dye laser has revolutionized
       treatment of PWS

IV. Miscellaneous

 A. Suntan - tan lines obvious
    1. Addison disease - diffuse hyperpigmentation; increased pigment of
     scars, gingiva, palmar creases; thin body habitus
     a. ACTH deficiency - no hyperpigmentation
 B. Juvenile xanthogranuloma - yellowish nodule with infiltration and
    proliferation of histiocytes, grows rapidly in infants and young children,
    resolves spontaneously, are not associated with lipid abnormalities
 C. Multiple JXG may be associated with non-traumatic hyphema.
 D. Linear nevus sebaceous may have 10%-15% risk of malignancy and if
    mid facial may be associated with seizures and mental retardation
 E Xanthoma - related to hypercholesterolemia, usually involving bony
prominences or tendons, disappear after successful treatment or liver
 F Bruising/bleeding
    1. Mongolian spots - slate gray dermal pigmentation, seen frequently in
     darker-skinned patients
    2. Normal toddler bruises
    3. Petechiae, purpura
     a. Henoch-Schoenlein purpura
     b. ITP
    4. Patterned bruises
     a. Unusual location - trunk, head, face
     b. Patterns of weapons - chain, rope, hand
     c. Bites
     d. Coining, cupping, pinching
     e. Bleeding from protein-energy malnutrition
          (1) Acral rash - acrodermatitis enteropathica, biotin deficiency
 G. Effects of immune deficiency
    1. Thrush, candida dermatitis, onychomycosis
    2. Molluscum
    3. Kaposi sarcoma
    4. White cell defects
    5. Warts
    6. Scabies
    7. Clubbing from interstitial pneumonitis
     a. Differential clubbing from differential cyanosis - reversed shunting
          through a patent ductus arteriosus in a patient with pulmonary
          vascular disease



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