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Pubic Lice InfestationDownload PDF version formatted for print
What are pubic lice?Also called "crabs," pubic lice are parasitic insects found in the genital area of humans. Infection is common and found worldwide. How did I get pubic lice?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 misunderstanding is that infestation can be spread by sitting on a toilet seat. This isn't 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. Where are pubic lice found?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, armpits, mustache, beard, eyebrows, or 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. What are the signs and symptoms of pubic lice?Signs and symptoms of pubic lice include
What do pubic lice look like?There are three stages in the life of a pubic louse: the nit, the nymph, and the adult. Nit: 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. Nymph: The nit hatches into a baby louse called a nymph. It looks like an adult pubic louse, but it is smaller. Nymphs mature into adults about 7 days after hatching. To live, the nymph must feed on blood. Adult: The adult pubic louse is about the size of this circle 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 is how they got the nickname "crabs." Pubic lice are tan to grayish-white in color. Females lay nits and are usually larger than males. To live, adult lice must feed on blood. If the louse falls off a person, it dies within 1-2 days. How is a pubic lice infestation diagnosed?A lice infestation is diagnosed by looking closely through pubic hair for nits, nymphs, or adults. It may be difficult to find nymph or adult; here 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. If you are unsure about infestation or if treatment is not successful, see a health care provider for a diagnosis. How is a pubic lice infestation treated?A lice-killing shampoo (also called a pediculicide) made of 1% permethrin or pyrethrin is recommended to treat pubic lice. These products are available without a prescription at your local drug store. Medication is generally very effective; apply the medication exactly as directed on the bottle. A prescription medication, called Lindane (1%) is available through your health care provider. Lindane is not recommended for pregnant or nursing women, or for children less than 2 years old. Malathion* lotion 0.5% (Ovide*) is another prescription medication that is effective against pubic lice. How to treat pubic lice infestations: (Note: see section below for treatment of eyelashes or eyebrows. The lice medications described in this section should not be used near the eyes.)
To treat nits and lice found on eyebrows or eyelashes:
*Use of trade names is for identification purposes only and does not imply endorsement by the Public Health Service or by the U.S. Department of Health and Human Services. This fact sheet is for information only and is not meant to be used for self-diagnosis or as a substitute for consultation with a health care provider. If you have any questions about the disease described above or think that you may have a parasitic infection, consult a health care provider. Revised October 19, 2004 Treating Head Lice Infestation |
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Info CDC Home | CDC Search | CDC Health Topics A-Z This page last reviewed October 21, 2004 Centers for Disease Control and Prevention
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