Pubic Lice (Crabs): How They Spread, Symptoms, Diagnosis and Treatment

Pubic lice — also called crabs — are tiny insects that usually live in the pubic or genital area of humans. They are sometimes found on other coarse body hair: the legs, armpits, mustache, beard, eyebrows or eyelashes. On the eyebrows or eyelashes of children or teens, pubic lice may be a sign of sexual exposure or abuse.

They are parasites that must feed on human blood to survive. They are one of three types of lice that live on humans, with head lice and body lice. Each type is different, and having one doesn't mean you'll get another.

How they spread

• Pubic lice crawl — they can't hop or fly.
• They usually spread through sexual contact.
• Occasionally, they spread through physical contact with someone who has them, or through clothing, beds, bed linens or towels that person used.
• You can't get pubic lice from animals.

Because they spread mainly through sex, they are most common in adults.

Symptoms

The most common symptom is intense itching in the genital area. You may also see nits (lice eggs) or crawling lice.

Diagnosis

Pubic lice are usually diagnosed by seeing a louse or a nit — which can be hard:

• there may be only a few;
• they often attach to more than one hair;
• they crawl more slowly than head and body lice.

A magnifying lens sometimes helps. Anyone with pubic lice should also be checked for other sexually transmitted infections (STIs), and their sexual partners should be checked for pubic lice.

Treatment

• The main treatment is a lice-killing lotion: a lotion with permethrin, or a mousse with pyrethrins and piperonyl butoxide. Both are sold over the counter, and are safe and effective used as directed.
• One treatment usually works. If not, you may need another after 9–10 days.
• Other lice-killing medicines are available by prescription.
• Wash clothes, bedding and towels in hot water, and dry them on the hot cycle.

Sources

Based on "Pubic Lice," MedlinePlus, National Library of Medicine, drawing on the Centers for Disease Control and Prevention; a work of the United States government in the public domain.