Pediculosis pubis diagnosis and management

Last updated: June 2013

Diagnosis

The diagnosis is suggested by a history of itching and exposure to lice or observation of crabs by the patient. Pubic lice can also involve eyelashes, eyebrows, beard and body hair and these areas should be examined.

Microscopy and clinical presentation

Observation of pubic lice and/or nits (eggs) attached to the hair and/or examination under light microscopy can confirm morphology if necessary.

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Treatment

Standard therapy

Permethrin 1% cream rinse topical from chest to knees washed off after 10 minutes with repeated treatment 1 week later (B2).

Note the following:

  • Permethrin should be applied to clean and cool skin. The patient should not take a hot bath or shower prior to treatment
  • apply to infected and adjacent hairy areas
  • nits should be removed with a fine toothed comb
  • sex partners should be treated concurrently
  • clothing and bed linen contaminated by the patient within the past 2 days should be washed and dried by machine (hot cycle) or dry cleaned.

Alternative therapy

Pyrethrins with piperonylbutoxide applied to the affected area and washed off after 10 minutes (B2) 

OR

Malathion (0.5%) lotion applied to dry hair and washed out after 8 hours.

Pregnancy and children

Pyrethrins are the preferred therapeutic option in pregnancy and children under one year of age.

Eye lash Infection

Apply occlusive sterile white soft paraffin (for example Lacri-Lube) to eyelid margins, and then remove the eggs, twice daily for 10 days.

Vaseline is not recommended as it is not sterile and can irritate the eyes if applied.

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Patient education

The following points should be discussed:

  • the nature of the infection
  • non-sexual transmission of crabs is possible, but in almost all instances transmission is the result of prolonged close physical contact
  • incubation period is typically between 5 days and several weeks
  • advise that the itch can last for a few days following treatment, oral anti-histamines may be useful particularly at night
  • the presence of pediculosis pubis, indicates the need for a complete sexually transmitted infection (STI)/human immunodeficiency virus (HIV) screen.

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Follow up

Required only if symptoms do not resolve.

If re-treatment is required, alternative regimens should be used and sources of re-infection sought and treated.

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Further information

For further information on the diagnosis and management of pediculosis pubis contact Adelaide Sexual Health Centre.

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Disclaimer

These guidelines are based on review of current literature, current recommendations of the United States Centers for Disease Control and Prevention, World Health Organization, the British Association for Sexual Health and HIV and local expert opinion.

They are written primarily for use by Adelaide Sexual Health Centre staff and some flexibility is required in applying them to certain private practice situations.

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