Definition of Pubic lice

Pubic lice: Parasitic insects found in the genital area of humans. Pubic lice are usually spread through sexual contact. Rarely, infestation can be spread through contact with an infested person's bed linens, towels, or clothes. A common misbelief is that infestation can be spread by sitting on a toilet seat. This is not likely, since lice cannot live long away from a warm human body. Also, lice do not have feet designed to walk or hold onto smooth surfaces such as toilet seats. Infection in a young child or teenager may indicate sexual activity or sexual abuse.

Pubic lice are generally found in the genital area on pubic hair; but may occasionally be found on other coarse body hair, such as hair on the legs, armpit, mustache, beard, eyebrows, and eyelashes. Infestations of young children are usually on the eyebrows or eyelashes. Lice found on the head are not pubic lice; they are head lice. Animals do not get or spread pubic lice.

There are three stages in the life of a pubic louse --nits, nymphs, and adults:

• Nits: Nits are pubic lice eggs. They are hard to see and are found firmly attached to the hair shaft. They are about the size of the mark at the end of this arrow . They are oval and usually yellow to white. Nits take about 1 week to hatch.
• Nymphs: The nit hatches into a baby louse called a nymph. It looks like an adult pubic louse, but is smaller. Nymphs mature into adults about 7 days after hatching. To live, the nymph must feed on blood.
• Adults: The adult pubic louse is about this size and resembles a miniature crab when viewed through a strong magnifying glass. Pubic lice have six legs, but their two front legs are very large and look like the pincher claws of a crab; this how they got the nickname "crabs." Pubic lice are tan to greyish-white in color. Females lay nits; they are usually larger than males. To live, adult lice need to feed on blood. If the louse falls off a person, it dies within 1-2 days.

The key symptom of pubic lice is itching in the genital area. Nits (lice eggs) or crawling lice may be seen. A pubic lice infestation is diagnosed by looking closely through pubic hair for nits, nymphs, or adults. Finding a nymph or adult may be difficult; there are usually few of them and they can move quickly away from light. If crawling lice are not seen, finding nits confirms that a person is infested and should be treated.

Treatment is with a 1% permethrin or pyrethrin lice shampoo, also called pediculicide peh-DICK-you-luh-side, is recommended to treat pubic lice. These products are available without a prescription at drug stores. A prescription medication, called Lindane (1%) is also available. Lindane is not recommended for pregnant or nursing women or for children less than 2 years old. To treat pubic lice infestations:

1. Wash the infested area; towel dry.
2. Thoroughly saturate hair with lice medication. If using permethrin or pyrethrins, leave medication on for 10 minutes; if using Lindane, shampoo should only be left on for 4 minutes. Thoroughly rinse off medication with water. Dry off with a clean towel.
3. Following treatment, most nits will still be attached to hair shafts. Nits may be removed with fingernails.
4. Put on clean underwear and clothing after treatment.
5. To kill any lice and nits that may be left on clothing or bedding, machine wash those washable items that the infested person used during the 2-3 days before treatment. Use the hot water cycle (130o F) of the washing machine to wash clothes. Use the hot cycle of the dryer for at least 20 minutes to dry clothes.
6. Dry clean clothing that is not washable.
7. Inform any sexual partners that they are at risk for infestation.
8. Avoid any sexual partners until partners have been treated and infestation has been cured.
9. Retreat in 7-10 days if lice are still found.

If only a few nits are found on eyebrows or eyelashes, it may be possible to remove the live lice and nits with fingernails or a nit comb. If additional treatment is needed for pubic lice nits found on the eyelashes, applying an ophthalmic-grade petrolatum ointment (only available by prescription) to the eyelids twice a day for 10 days is effective.

Picture of pubic louse (crab)