What are pubic lice?

Pubic lice (Phthirus pubis) are small parasitic insects. A single insect is called a louse. They mostly live in the genital areas of humans. In some cases, they can also be found on other areas of the body that have hair. They are most often spread through sexual contact. Pubic lice affect men and women at all levels of society all over the world. Teens and people in their 20s are most often affected. But children and older adults can also get pubic lice. Some studies are showing pubic lice cases are decreasing because of genital hair removal methods like shaving and waxing.

Lice have 3 different phases in their life cycle:

• Nits. These are tiny lice eggs that firmly attach to a shaft of hair. They are yellow or white, and they can be hard to see.

• Nymphs. A nymph is an immature louse that has just hatched from a nit. It looks like a smaller adult louse.

• Adults. An adult louse looks like a tiny crab. Because of this, they are sometimes called crabs. Adult lice are about 1 millimeter long. They can be hard to see unless they have just fed.

Nymphs and adults are parasites and must feed on human blood to survive. If a louse falls off a person, it will die within a day or two.

Pubic lice are not the same thing as head lice or body lice. These are caused by different species of insect that live on other areas of the body. Head lice live on the head, eyebrows, or eyelashes. Body lice live mostly on clothing and bedding. Unlike other kinds of lice, such as body lice, pubic lice don’t spread disease.

What causes pubic lice?

Pubic lice spread most often through sexual contact. Less often, you may get pubic lice from other types of close contact with a person, or by touching clothing, sheets, or towels that someone with pubic lice has used. It's unlikely to get pubic lice from sitting on a toilet seat that an infected person has used. This is because lice don’t have feet that enable them to walk on a smooth surface.

Animals don’t get pubic lice, and they play no role in its spread.

Who is at risk for pubic lice?

You have an increased risk for pubic lice if you have sexual contact with someone who has them.

What are the symptoms of pubic lice?

Itching of the genital area is the most common symptom caused by pubic lice. Itching of the armpits is also common.

Usually, pubic lice live on pubic hair in the genital area. If you look carefully, you may be able to see visible nits or crawling lice. Less commonly, they live on hair on other parts of your body. This may include legs, armpits, beard, eyebrows, eyelashes, or on your head. Usually lice on the head are head lice, not pubic lice. Pubic lice on the eyelashes may cause eye burning or irritation.

Pubic lice on the eyebrows or eyelashes of children may be a sign of sexual abuse. More often, this is caused by shared household items, such as towels, or from close contact with nongenital infestation sites on an adult.

How are pubic lice diagnosed?

Your healthcare provider can diagnose you by finding a pubic louse or nit in your genital area (or less commonly, in other areas). Nits and lice are sometimes large enough to see with the naked eye, but a healthcare provider may use a magnifying glass to help with diagnosis. Adult lice may be harder to see because there may only be a few. If you have lice outside your genital area, your healthcare provider will examine them to confirm that they are pubic lice and not head or body lice.

If you have pubic lice, you may have tests for other types of sexually transmitted infections (STIs). These may include tests for chlamydia and HIV. That’s because a large number of people with pubic lice also have an STI.

How are pubic lice treated?

Pubic lice can be treated with a lotion that contains the chemical permethrin or a cream containing pyrethrin and piperonyl butoxide. These are available as over-the-counter treatments or by a prescription. They work well when used correctly.                                                                 

Follow the directions on the package of the lotion or cream. Make sure to:

• Use the treatment when your skin is cool and dry.

• Apply the treatment to the skin and hair in your pubic area and the skin around the anus. Don’t place it inside the vagina or rectum.

• Do the same with other hairy areas, like your underarms, chest, back, and thighs.

• Rinse off the treatment according to the package instructions, usually about 10 minutes later.

• After the treatment, remove any lice that you see. Do this with your fingers, a fine-tooth comb, or with tweezers.

• Remove nits with a fine-tooth comb.

• Put on clean clothes and underwear after treatment.

Also make sure to wash any clothing, towels, or bedding used in the 3 days before your treatment. Use hot water and dry the items on the hottest setting. Or you can dry-clean the clothes. For items that can’t be washed or dry-cleaned, place them in a sealed plastic bag for 2 weeks. This will starve any remaining lice.

The treatment should work quickly. If you continue to have itchiness a week after treatment, see your healthcare provider. You may need a repeat treatment at that time.

If you have lice in your eyelashes, your treatment may be different. You’ll likely need to coat your eyelashes with petroleum jelly twice a day for about a week. This will be a prescription type of petroleum jelly that won’t irritate your eyes. It will loosen the lice and nits so you can remove them. In more severe cases, you may need another prescription treatment.

Make sure to tell your sexual partners that you have pubic lice. They will need to be diagnosed and treated. Tell anyone that you had sex within the last month. Don’t have any sexual contact until you have been treated and your healthcare provider says you are lice-free.

What are possible complications of pubic lice?

Pubic lice on the eyelids can lead to an inflamed lining of the eye (conjunctivitis).

Excess scratching due to itching may lead to an infection. This may need to be treated with antibiotics.

Key points about pubic lice

• Pubic lice are parasitic insects that live mostly in the genital areas of humans. They are most often spread through sexual contact. They are not the same as head lice or body lice.

• People from all social backgrounds can get pubic lice.

• Pubic lice usually affect the genital areas, but they may also be found in other areas of the body that have hair.

• If you have pubic lice, you may also need testing for other sexually transmitted infections.

• Over-the-counter medicines often work well to treat pubic lice.

• Make sure to tell all your sexual partners that you have pubic lice, so they can also be diagnosed and treated.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

• Know the reason for your visit and what you want to happen.

• Before your visit, write down questions you want answered.

• Bring someone with you to help you ask questions and remember what your provider tells you.

• At the visit, write down the name of a new diagnosis and any new medicines, treatments, or tests. Also write down any new instructions your provider gives you.

• Know why a new medicine or treatment is prescribed and how it will help you. Also know what the side effects are.

• Ask if your condition can be treated in other ways.

• Know why a test or procedure is recommended and what the results could mean.

• Know what to expect if you do not take the medicine or have the test or procedure.

• If you have a follow-up appointment, write down the date, time, and purpose for that visit.

• Know how you can contact your healthcare provider if you have questions, especially after office hours and on weekends and holidays.