Pediculosis Pubis (Crabs, Pubic Lice)

Pubic lice (pediculosis pubis) is caused by the infestation of the pubic hair and skin by tiny organisms that are just at the limits of visibility without magnification.

Pubic lice can be spread through sexual contact, close living quarters, or shared clothing.

The patient will described moderately intense itching and may say, "I think I see something moving down there."

Ideally, the patient is examined with good lighting and a magnifying lens. The lice can be seen moving along the shafts of the pubic hair. Individual "nits" can be seen. These are small, oval, gray eggs attached to the hairs. Brown discolorations of the skin, when closely examined, are seen to contain lice excrement deposited just beneath the skin.

Without magnification, the brown spots can be seen, but most noticeable is the movement of the lice.

Treatment may include:

• Nix cream (5% permethrin) applied to the vulvar skin and left in place for 6-12 hours before washing off.

• Kwell lotion or shampoo (1% lindane) once after showering and left in place for 10 minutes before rinsing. This may be repeated in 7 days if necessary. Do not use more often or longer than this as lindane has neurotoxicity potential.

• Mechanically removing nits and lice by combing the pubic hair with a fine toothed comb.

• Clothing and bed linens should be thoroughly washed and dried. Mattresses should be aired or vacuumed. Sources of cross-contamination (shared clothing, towels) eliminated. Sexual contacts should be treated.

If conventional medication is not available, petroleum jelly, applied to the affected area may prove effective by suffocating the lice.