Pubic Lice (Crabs)

What Are Pubic Lice?

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Also called crab lice or "crabs," pubic lice are parasitic insects found primarily in the pubic or genital area of humans. Pubic lice infestation is found worldwide and occurs in all races, ethnic groups, and levels of society.

What Do Pubic Lice Look Like?

Pubic lice have forms: the egg (also called a nit), the nymph, and the adult.

Nit: Nits are lice eggs. They can be hard to see and are found firmly attached to the hair shaft. They are oval and usually yellow to white. Pubic lice nits take about 6-10 days to hatch.

Nymph: The nymph is an immature louse that hatches from the nit (egg). A nymph looks like an adult pubic louse but it is smaller. Pubic lice nymphs take about 2-3 weeks after hatching to mature into adults capable of reproducing. To live, a nymph must feed on blood.

Adult: The adult pubic louse resembles a miniature crab when viewed through a strong magnifying glass. Pubic lice have six legs; 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, lice must feed on blood. If the louse falls off a person, it dies within 1-2 days.

Picture of pubic louse (crab)
Picture of pubic louse (crab)

Where Are Pubic Lice Found?

Pubic lice usually are found in the genital area on pubic hair; but they may occasionally be found on other coarse body hair, such as hair on the legs, armpits, mustache, beard, eyebrows, or eyelashes. Pubic lice on the eyebrows or eyelashes of children may be a sign of sexual exposure or abuse. Lice found on the head generally head lice, not pubic lice.

Animals do not get or spread pubic lice.

Medically Reviewed by a Doctor on 3/14/2014

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Pubic Lice (Crabs) - Treatment Question: What kinds of treatment, including medication, did you or your partner receive for public lice (crabs)?
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Pubic Lice (Crabs)

How to identify pubic lice

Adult pubic lice are 1.1-1.8 mm in length. Pubic lice typically are found attached to hair in the pubic area but sometimes are found on coarse hair elsewhere on the body (for example, eyebrows, eyelashes, beard, mustache, chest, armpits, etc.).

Pubic lice infestations (pthiriasis) are usually spread through sexual contact. Dogs, cats, and other pets do not play a role in the transmission of human lice.

Both over-the-counter and prescription medications are available for treatment of pubic lice infestations.

SOURCE: Centers for Disease Control and Prevention. Pubic "Crab" Lice Fact Sheet.

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