Pubic Lice

Pubic lice, commonly referred to as "crabs" are small, crab-shaped insects (Pthirus pubis), which attach themselves to human hairs.  Crabs usually live in the pubic hair but can sometimes be found in axillary or armpit hair, facial hair, or even eyelashes.  Infection is common and found worldwide.

Pubic lice occur when adult lice lay eggs, called nits, on the hair shaft close to the skin.  The egg, which is white to yellow and oval shaped, requires 7-10 days to hatch into a nymph.  Nymphs and adult lice feed on human blood.

It is possible to be infested with pubic lice and have no symptoms.  More commonly, itching occurs, which worsens at night.  Pubic lice are difficult to see because of their location and appearance.  Grayish-white lice blend in with white skin and brown lice can be mistaken for moles or can be hard to see on black skin.  A rash or faint bluish spots might be noted at the site of bites.  If lice infest the eyebrows or eyelashes, the eyes may become inflamed.

Pubic lice are usually transmitted through direct physical contact, especially of the genital areas.  Occasionally transmission can occur through contact with an infested person's sheets, towels or clothes, as they can survive without a human host for one to two days.  They are rarely transmitted from furniture or toilet seats because the lice that fall from their host are usually injured or dying.  Lice cannot jump from person to person, nor can they be transmitted to or by animals.  Infestation with pubic lice and the development of noticeable symptoms may occur immediately, or may be delayed 2-4 weeks if eggs have not hatched.

Because pubic lice and their eggs are not affected by ordinary soap and water, your health care provider will recommend a medication to destroy the lice.  Permethrin 1% crème rinse is most commonly used, and a single treatment is almost always effective.  This is available without a prescription through the pharmacy. It is important that you read all of the directions before beginning, and follow them precisely.

Treatment procedure for crab lice (using Permethrin 1% crème rinse):

  1. Wash pubic hair; towel dry.

  2. Saturate hair with crème rinse; leave on for 10 minutes; thoroughly rinse off with water; dry with a clean towel.

  3. Following treatment, nits may still be attached to hair shafts.  Comb with a fine-tooth comb or use tweezers or fingernails to remove nits.

Once the lice have been destroyed by treatment, it is important to take the following measures to prevent re-infestation.

  1. Put on clean clothing following treatment.

  2. Machine wash all clothing (especially undergarments), towels, bed linen and any items that have come in contact with the skin since the onset of symptoms. Items that cannot be laundered may be dry cleaned, or wrapped in a plastic bag for 30 days.

  3. Sanitize the bathroom and shower.  You may use bathroom cleaner or bleach solution.

  4. Inform others with whom you have had recent intimate contact so they can be examined for signs of infestation.

  5. Avoid intimate contact until condition is resolved and partners, if infested, have also completed treatment.

  6. Re-treat one time only in 7-10 days if lice are still found.  Seek medical assistance if the problem persists.

If only a few nits or lice are found then you may be able to remove them with your fingernails or by using a RIT comb.  If additional treatment is needed then see your health care provider as a prescription for an opthamalic-grade petrolatum ointment may be needed.  DO NOT USE Permethrin or pryethrin products on your face - near eyes or mouth.

It is common to have itching present after treatment for 1-2 weeks due to the allergic reaction from the bites.  Contact your healthcare provider if you have any of the following problems: