Previous version Pubic lice Treatment of pubic lice by coreymcintyre

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									Clinical Knowledge Summaries: Previous version: Pubic lice




Previous version: Pubic lice
This PRODIGY guidance topic is obsolete and has been replaced by a CKS Topic Review.
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About this topic
Have I got the right topic?
Age from 6 months onwards
This guidance covers the management of pubic or crab lice infestation (pediculosis pubis).
There are separate CKS topics on Head lice and Scabies.
The target audience for this guidance is healthcare professionals working within the NHS in
England, and providing first contact or primary health care. The Shared decision making sections
are designed to provide a focus for discussion during the consultation about the treatment
options.
Changes
Last revised in February 2004
October 2005 — minor technical update. Issued in November 2005.
Previous changes
August 2003 — reviewed. Validated in December 2003 and issued in February 2004.
November 2000 — rewritten. Validated in March 2001 and issued in June 2001.
June 1998 — reviewed.
September 1997 — written.
Update
New evidence
Evidence-based guidelines
No new evidence-based guidelines since 1 March 2007.
HTAs (Health Technology Assessments)
No new HTAs since 1 March 2007.
Economic appraisals
No new economic appraisals relevant to England since 1 March 2007.
Systematic reviews and meta-analyses
No new systematic review or meta-analysis since 1 March 2007.
Primary evidence
No new high quality randomized controlled trials since 1 March 2007.
New policies
No new national policies or guidelines since 1 March 2007.
New safety alerts
No new safety alerts since 1 March 2007.
Changes in product availability
No changes in product availability since 1 March 2007.

Concise knowledge for clinical scenarios
Treatment of pubic lice
Which therapy?
    •    Adult lice and/or eggs need to be found to confirm the diagnosis.
    •    Sexual contacts and close family contacts should be examined, and treated if
         infested.
    •    Give two applications of insecticide, used 7 days apart.
              o    Use malathion 0.5% aqueous liquid, phenothrin 0.5% aqueous liquid, or
                   permethrin 5% dermal cream.
              o    Give 100 ml liquid or 30 g cream per application.


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               o   Advise people to inspect the body 1 week after the final application to check
                   that treatment was successful.
    •    If itching is troublesome, oral sedative antihistamines given at night may be useful
         for breaking the itch–scratch cycle.
    •    Screening for coexisting sexually transmitted infections is recommended.
         (Note: people need to give informed consent prior to screening.) Consider referral to a
         genito-urinary medicine clinic.
    •    If treatment failure or reinfestation occurs, use a different insecticide for the
         second course of treatment.
Factors affecting choice of treatment
    •    Pregnancy and breastfeeding: use a single application of malathion (in an aqueous
         base). If this is ineffective, consider a second application after an interval of at least
         7 days. Consider chlorphenamine (chlorpheniramine) to relieve itch. Do not use
         hydroxyzine.
    •    Benign prostatic hyperplasia, urinary retention, or glaucoma: avoid sedating
         antihistamines.
    •    Epilepsy: avoid antihistamines (which may lower the seizure threshold).
Practical prescribing points
For further information please see the Medicines Compendium (www.medicines.org.uk) or the
British National Formulary (www.bnf.org). For further information regarding pregnancy, contact
the National Teratology Information Service (telephone 0191 232 152).
    •    Apply treatment to all parts of the body below the neck (not merely the groin
         and axillae).
             o     Apply malathion or phenothrin aqueous liquids for 12 hours or overnight.
             o     Apply permethrin 5% dermal cream for 24 hours.
    •    Beards and moustaches should be carefully treated, but not usually other
         areas of the head unless the hair is widely spaced (e.g. in red hair).
    •    Shaving the infested area(s) does not provide protection from reinfestation.
    •    Advise the person that sedative antihistamines cause drowsiness, which may
         persist the next day. People should not drive or operate machinery if affected.
Should I refer or investigate?
Refer?
    •    Consider referral to a genito-urinary medicine clinic for specialist advice,
         diagnostic services, and partner notification. Contact-tracing of partners from the
         previous 3 months should be undertaken.
Investigate?
    •    Screening for coexisting sexually transmitted infections is recommended.
         (Note: people need to give informed consent prior to screening.)
Follow-up advice
    •    People should be advised to check for the absence of lice 1 week after the
         second application of treatment, to confirm that treatment was successful.
    •    If treatment failure or reinfestation occurs, a different insecticide should be used
         for the second course of treatment.

Prescriptions
Usual treatment options
Aqueous-based liquid: malathion
Age from 6 months onwards
    •    Malathion 0.5% aqueous liquid. Apply to the whole body from the neck down. Leave on
         for 12 hours or overnight. Wash off. Repeat after 7 days. Supply 200 ml.
    •    NHS Cost £5.28
    •    OTC Cost £9.25
    •    Licensed use: no
    •    Patient Information: Apply to the entire skin surface from the neck down, especially
         pubic hair, hair around the anus, between the legs, and other hairy areas of the body.
         Apply to beards and moustaches but not to non hairy areas of the face and neck
         (100ml should be enough for each application). Leave on for 12 hours or overnight.
         Then wash off. Repeat after 7 days.
Aqueous-based liquid: phenothrin
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Age from 6 months onwards
    •   Phenothrin 0.5% liquid. Apply to the whole body from the neck down. Leave on for 12
        hours or overnight. Wash off. Repeat after 7 days. Supply 200 ml.
    •   NHS Cost £5.28
    •   OTC Cost £9.25
    •   Licensed use: no
    •   Patient Information: Apply to the entire skin surface from the neck down, especially
        pubic hair, hair around the anus, between the legs, and other hairy areas of the body.
        Apply to beards and moustaches but not to non hairy areas of the face and neck
        (100ml should be enough for each application). Leave on for 12 hours or overnight.
        Then wash off. Repeat after 7 days.
Dermal cream: permethrin
Age from 18 years onwards
    •   Permethrin 5% cream. Apply to all hairy parts of the body. Leave on for 24 hours.
        Wash off. Repeat after 7 days. Supply 60 grams.
    •   NHS Cost £11.04
    •   OTC Cost £19.24
    •   Licensed use: no
    •   Patient Information: Apply this cream to all hairy parts of the body, especially pubic
        hair, hair around the anus, between the legs and the chest (two-thirds of a tube should
        be enough). Do not put on to non-hairy areas of the face and neck. Leave on for 24
        hours. Then wash off. Repeat after 7 days.
Pregnancy and breastfeeding
Aqueous-based liquid: malathion
Age from 12 to 60 years
    •   Malathion 0.5% aqueous liquid. Apply to the whole body from the neck down. Leave on
        for 12 hours or overnight. Wash off. Supply 100 ml.
    •   NHS Cost £4.44
    •   Licensed use: no
    •   Patient Information: Apply to entire skin surface from the neck down, especially pubic
        hair, hair around the anus, between the legs and other hairy areas of the body (100ml
        should be enough). Leave on for 12 hours or overnight. Then wash off.
Sedating antihistamine (for sleep disturbance)
Chlorphenamine (chlorpheniramine) syrup: 1mg at night prn
Age from 6 to 11 months
    •   Chlorphenamine 2mg/5ml oral solution. Take 2.5ml at night when required for relief of
        itching. Supply 50 ml.
    •   NHS Cost £0.72
    •   Licensed use: no
Chlorphenamine (chlorpheniramine) syrup: 1mg at night prn
Age from 1 year to 1 year 11 months
    •   Chlorphenamine 2mg/5ml oral solution. Take 2.5ml at night when required for relief of
        itching. Supply 50 ml.
    •   NHS Cost £0.72
    •   OTC Cost £1.26
    •   Licensed use: yes
    •   Patient Information: You can buy chlorphenamine (chlorpheniramine) syrup from a
        pharmacy.
Chlorphenamine (chlorpheniramine) syrup: 1-2mg at night prn
Age from 2 years to 5 years 11 months
    •   Chlorphenamine 2mg/5ml oral solution. Take 2.5ml to 5ml at night when required for
        relief of itching. Supply 100 ml.
    •   NHS Cost £1.43
    •   OTC Cost £2.53
    •   Licensed use: yes
    •   Patient Information: You can buy chlorphenamine (chlorpheniramine) syrup from a
        pharmacy.

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Chlorphenamine (chlorpheniramine) syrup: 2-4mg at night prn
Age from 6 years to 11 years 11 months
    •    Chlorphenamine 2mg/5ml oral solution. Take one to two 5ml spoonfuls at night when
         required for relief of itching. Supply 100 ml.
    •    NHS Cost £1.43
    •    OTC Cost £2.53
    •    Licensed use: yes
    •    Patient Information: You can buy chlorphenamine (chlorpheniramine) syrup from a
         pharmacy.
Chlorphenamine (chlorpheniramine) tablets: 4mg at night prn
Age from 12 years onwards
    •    Chlorphenamine 4mg tablets. Take one tablet at night when required for relief of
         itching. Supply 14 tablets.
    •    NHS Cost £0.22
    •    OTC Cost £1.40
    •    Licensed use: yes
    •    Patient Information: You can buy chlorphenamine (chlorpheniramine) tablets from a
         pharmacy.
Hydroxyzine syrup: 5mg to 15mg at night when required
Age from 6 months to 6 years 11 months
    •    Hydroxyzine 10mg/5ml oral solution. Take 2.5ml to 7.5ml at night when required for
         relief of itching. Supply 100 ml.
    •    NHS Cost £0.96
    •    Licensed use: yes
Hydroxyzine syrup: 15mg to 25mg at night when required
Age from 7 years to 11 years 11 months
    •    Hydroxyzine 10mg/5ml oral solution. Take 7.5ml to 12.5ml at night when required for
         relief of itching. Supply 200 ml.
    •    NHS Cost £1.91
    •    Licensed use: yes
Hydroxyzine tablets: 25mg at night when required
Age from 12 years onwards
    •    Hydroxyzine 25mg tablets. Take one tablet at night when required for relief of itching.
         Supply 14 tablets.
    •    NHS Cost £0.51
    •    Licensed use: yes
Drug rationale
Drugs not included
Treatment of pubic lice
    •    Alcohol-based products are not included, because they irritate excoriated skin and
         genitalia.
    •    Benzyl benzoate is licensed for the treatment of pubic lice, but is not included
         because it causes irritation, especially to the genitals.
    •    Carbaryl should be considered only when resistance to all other insecticides is
         suspected. Carbaryl is now a prescription-only medicine (because of reports of
         carcinogenicity in rodents after continuous dosing) [CMO, 1995] and is no longer
         licensed for treating pubic lice.
Treatment of itch
    •    Non-sedative antihistamines have not been shown to be effective in relieving
         pruritus. Sedative effects may be desirable to help break the itch–scratch cycle at
         night.
    •    Long-acting sedating antihistamines are not included, so there is minimal
         ‘hangover’ effect.
    •    Topical antihistamines may cause sensitization, are only marginally effective, and
         are therefore not recommended.
    •    Preparations containing calamine do not offer significant benefit in most people,
         and are not recommended.
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Drugs included
Treatment of pubic lice
    •    Aqueous-based products are preferred because they are less likely to irritate
         excoriated skin and the genitalia, or to cause wheezing in people with asthma [BNF 45,
         2003].
    •    Malathion 0.5% aqueous liquid is licensed for the treatment of pubic lice.
    •    Phenothrin 0.5% aqueous liquid is an alternative, but this is an off-licence use.
    •    Permethrin 5% dermal cream is also licensed for the treatment of pubic lice, but
         only for adults.
Treatment of itch
    •    Hydroxyzine is specifically licensed for pruritus and is sedating. Hydroxyzine is offered
         as a night-time dose for temporary help with sleeping, to help break the itch–scratch
         cycle.
    •    Chlorphenamine (chlorpheniramine) is also included because it is inexpensive, and
         is an effective sedating antihistamine of intermediate duration.
Shared decision making
    •    Pubic lice can affect other parts of the body — not just the pubic area.
    •    Treat the whole body below the neck, plus any beard and moustache, but not
         the rest of the head. (Avoid eyes and mouth.) Options include:
              o    Malathion lotion. Leave it on for 12 hours, then wash it off. An adult needs
                   about 100 ml. A small paintbrush may be helpful in applying it.
              o    Permethrin cream. Leave it on for 24 hours, then wash it off. The cream is
                   not suitable for pregnant or breastfeeding women, or for children.
    •    You need two treatments, seven days apart.
    •    Occasionally, some people (e.g. those with red hair) may need to apply treatment to
         the scalp as well.
    •    Antihistamine tablets may help with itch, which can last for a few days after
         treatment.
    •    You do not need to shave affected areas or wash bedding, clothes, and so on.
    •    Avoid close bodily contact until you have finished treatment.
    •    All close contacts and sleeping partners should be checked.

Detailed knowledge about this topic
Goals and outcome measures
Goals
    •    To eradicate live pubic lice and viable eggs
Background information
What is it?
    •    The pubic louse is ‘crab’ shaped, grey-brown in colour, and about 2 mm in length
         (smaller than a match-head).
    •    The female lays eggs (smaller than a pinhead) on the hair shaft, near to the body. The
         eggs hatch after about 7 days. The empty eggshells (nits) are tightly attached to the
         hair and cannot be brushed off.
[Ibarra, 1998]
How common is it?
    •    The exact incidence of pubic lice is unknown, but it is thought to be quite common
         among young adults.
[Ibarra, 1998]
How do I know my patient has it?
    •    Itching is the most common presenting symptom, and is due to hypersensitivity
         to feeding lice. Itching is worse at night and may not develop for several weeks.
    •    Adult lice and/or eggs need to be found to confirm the diagnosis.
    •    Pubic lice may be found in any coarse hair, such as moustaches, beards, and
         axillary hair, as well as pubic hair. Therefore, all hairy parts of the body may need to be
         examined.
    •    The eyebrows and eyelashes can also be affected, but this generally occurs only
         in young children.
    •    Pubic lice can also be found around the scalp margins. Lice are most likely to be
         found when the hair shafts are widely spaced (e.g. in red hair).

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    •     Blue macules (maculae caerulae) may be visible at feeding sites.
    •     Scatterings of minute dark-brown specks (louse excreta) are sometimes seen on
          the skin and underwear.
[Burns, 1998; Ibarra, 1998; Wendel and Rompalo, 2002]
How is it transmitted?
    •     Pubic lice are transmitted by close body contact, which can be from sexual
          contact or from close family contact (e.g. from an infested beard or chest).
    •     Pubic lice are not transmitted via clothing, bed linen, or toilet seats.
[Ibarra, 1998; Wendel and Rompalo, 2002]
What else might it be?
    •     Seborrhoeic scales, small crusts of scratched dermatitis, and hair casts (which
          can all be brushed off) may be confused with nits (which stick to the hair like glue).
    •     Clothing lice (Pediculus humanis) and head lice (Pediculus capitis) are slightly
          larger than pubic lice. Clothing lice are found only on clothes, not on body hairs. Head
          lice are found only on the scalp.
Management issues
General
    •     Sexual contacts and close family contacts should be examined, and treated if
          infested.
    •     Screening for coexisting sexually transmitted infections is recommended.
          (Note: people need to give informed consent prior to screening.)
    •     Consider referral to a genito-urinary medicine clinic for specialist advice, diagnostic
          services, and partner notification.
    •     Contact-tracing of partners from the previous 3 months should be undertaken.
[Scott, 2001]
How should I treat pubic lice?
    •     Two applications of insecticide are used 7 days apart. (The second application of
          insecticide is used to kill pubic lice emerging from eggs that survived the first
          application.)
    •     Use malathion 0.5% aqueous liquid, permethrin 5% dermal cream, or
          phenothrin 0.5% aqueous liquid. Note: permethrin dermal cream is licensed for use
          only in those over 18 years of age, and phenothrin aqueous liquid is not licensed for
          the treatment of pubic lice.
    •     People should be advised to check for the absence of lice 1 week after
          treatment is complete, to ensure that treatment was successful.
    •     Shaving the infested area(s) will not provide protection from reinfestation,
          because pubic lice need only a minimal length of hair on which to lay eggs.
How should treatment be applied?
    •     Treatment should be applied to all parts of the body (not merely the groin and
          axillae) [BNF 45, 2003]. Beards and moustaches should be carefully treated, but not
          usually other areas of the head.
    •     Consider treating the scalp if the hair is widely spaced (e.g. for red hair) [Ibarra,
          1998].
    •     Aqueous-based liquids should be applied for 12 hours or overnight (e.g.
          malathion or phenothrin). Permethrin 5% dermal cream should be applied for 24 hours.
Treatment of itch
    •     Antihistamines are of little help in treating pruritus [DTB, 2002].
    •     However, it may be useful to give an oral sedative antihistamine at night for
          temporary help with sleeping, to break the itch–scratch cycle.
Eyelash infestation
    •     Pubic lice can occasionally infest the eyelashes, but this generally only occurs in
          young children.
    •     Petroleum jelly can be applied to the lashes and lids twice a day for 10 days [Clinical
          Effectiveness Group, 1999].
    •     Aqueous malathion or permethrin 1% cream rinse have also been used, but they are
          not licensed for this indication. Permethrin 5% dermal cream can cause irritation to the
          eyes, so it should not be used [Rundle and Hughes, 1993; Ibarra, 1998; Clinical
          Effectiveness Group, 1999; ABPI Medicines Compendium, 2001; BNF 45, 2003].
Treatment failure



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    •    Before using another course of treatment, consider whether treatment failure
         could be due to inadequate treatment, incorrectly applied treatment, misdiagnosis, or
         reinfestation (e.g. were all infested contacts treated?).
    •    Use a different class of insecticide for the second course of treatment. This
         change reduces repeated exposure to the same insecticide, and it is hoped that
         resistance will emerge more slowly as a result (although resistance of pubic lice to
         insecticides has not been studied in the UK). Note: permethrin and phenothrin are from
         the same chemical class (pyrethroids).
    •    Carbaryl should be considered only when resistance to all other insecticides is
         suspected. There are no longer any carbaryl preparations licensed for the treatment of
         pubic lice available in the UK, and it is now a prescription-only medicine (licensed for
         the treatment of head lice) because of reports of carcinogenicity in rodents after
         continuous dosing [CMO, 1995].
Medicines management
Insecticides
    •    Aqueous-based preparations are preferred (for both adults and children). Alcoholic
         lotions are not recommended, because they irritate excoriated skin and genitalia, and
         may cause wheezing in people with asthma.
    •    For each application, 100 ml of liquid or 30 g of cream is needed to treat an
         average-sized adult.
    •    Concerns have been raised in the past that topical malathion (an organophosphate)
         could potentially cause serious systemic adverse effects. However, a recent Committee
         on Safety of Medicines review concluded there is no evidence to suggest that this is the
         case [CSM, 2000].
    •    Children: malathion can be used for children aged over 6 months (note: pubic lice
         infestation is likely to occur only on the eyelashes in children younger than this).
         Permethrin is only licensed for the treatment of adults aged 18 years or over.
Sedating antihistamines
    •    Advise people that drowsiness may persist the next day, and that they should
         not drive or operate machinery if affected.
    •    Antimuscarinic adverse effects (sedation, dry mouth, urinary retention, blurred
         vision) are common. Sedating antihistamines should therefore be avoided in someone
         with prostatic hypertrophy, urinary retention, or glaucoma. Antihistamines may also
         reduce the seizure threshold, and so should be avoided in someone with epilepsy.
Pregnancy and breastfeeding
    •    The National Teratology Information Service currently recommends malathion
         because it is poorly absorbed and rapidly eliminated. A single application should be
         used where possible. If a single dose is ineffective, a second application could be
         considered after an interval of at least 7 days (telephone 0191 232 1525 for further
         information) [NTIS, 1999].
    •    Breastfeeding mothers should remove the liquid or cream from the nipples before
         breastfeeding, and reapply treatment afterwards.
    •    If treatment of itch is required, consider chlorphenamine (chlorpheniramine). Avoid
         hydroxyzine, crotamiton, and topical steroid creams.

References
NHS staff in England can link, free of charge, from references to the full text journal
articles by clicking on [NHS Full-text]. You will need an NHS Athens password to access
these resources. Click here for Athens registration.
All references with links to [Free Full-text] are freely available online to users in
England and Wales. This includes the full text of Department of Health papers and Cochrane
Library reviews.
1   ABPI Medicines Compendium (2001) Summary of product characteristics for Lyclear Dermal
    Cream. Datapharm Communications Ltd. www.emc.medicines.org.uk [Accessed:
    23/08/2003].
2   BNF 45 (2003) British National Formulary. 45th edn. London: British Medical Association and
    Royal Pharmaceutical Society of Great Britain.
3   Burns, D.A. (1998) Diseases caused by arthropods and other noxious animals: Phthiriasis
    pubis. In: Champion, R.H., Burton, J.L., Burns, D.A. and Breathnach, S.M. (Eds.) Textbook
    of dermatology. Oxford: Blackwell Science Ltd. 1443-1444.
4   Clinical Effectiveness Group (1999) National guideline for the management of phthirus pubis
    infestation. London: Assoication for Genitourinary Medicine and the Medical Society for the
    Study of Veneral Disease.


This PRODIGY guidance topic is obsolete and has been replaced by a CKS Topic Review.
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Clinical Knowledge Summaries: Previous version: Pubic lice



5    CMO (1995) New advice to government on use of insecticide as a treatment for lice: experts
     advise restricted use of carbaryl. Department of Health. www.dh.gov.uk [Accessed:
     16/05/2007]. [Free Full-text]
6    CSM (2000) Safety of malathion for the treatment of louse and scabies infestation. Current
     Problems in Pharmacovigilance 26(May), 2. [Free Full-text]
7    DTB (2002) Oral antihistamines for allergic disorders. Drug & Therapeutics Bulletin 40(8),
     59-62.
8    Ibarra, J. (1998) Phthiriasis. In: Figueroa, J., Hall, S. and Ibarra, J. (Eds.) Primary health
     care guide to common UK parasitic diseases. London: Community Hygiene Concern. 21-24.
9    NTIS (1999) Management of scabies and head lice in pregnancy. Newcastle upon Tyne:
     National Teratology Information Service, Regional Drug and Therapeutics Centre.
10   Rundle, P.A. and Hughes, D.S. (1993) Phthirus pubis infestation of the eyelids. British
     Journal of Ophthalmology 77(12), 815-816.
11   Scott, G.R. (2001) European guideline for the management of pediculosis pubis.
     International Journal of STD & AIDS 12(Suppl 3), 62. [NHS Athens Full-text]
12   Wendel, K. and Rompalo, A. (2002) Scabies and pediculosis pubis: an update of treatment
     regimens and general review. Clinical Infectious Diseases 35(Suppl 2), S146-S151. [Free
     Full-text]

Quick Reference Guide
     •    Pubic lice




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