Pubic Lice

This factsheet is for people who have pubic lice or who would like information about them.

Public lice are insects which live in the pubic hair, but they can infect other hair on the body including eyebrows and eyelashes. Pubic lice, or crab lice, can be embarrassing and are sometimes uncomfortable and itchy. They don't usually cause an illness. They won't clear up on their own and you need to treat them promptly.

About pubic lice
Pubic lice (pediculosis pubis) are also known as crabs. They are wingless insects, are dark grey or brown, have six legs and are about 2mm in long, when fully grown. They generally live on the coarse hair around the genitals and anus, but they can be found on the eyelashes, abdomen (tummy), back, armpit and head. They live off human blood.

Female lice lay eggs that are smaller than a pinhead and these attach to the bottom of the hair. The eggs hatch about six to 10 days later.

When lice hatch, they leave empty shells, called nits, which stick to the hair. You may mistake them for flakes of dry skin. Unlike dandruff, nits stick to the hair and you won't be able to remove them with normal shampooing.

Symptoms of pubic lice
Pubic lice can be itchy, particularly at night. However, you can have pubic lice and may not have any itching at all.

If you scratch a lot, the skin can become broken and inflamed making infections more likely to develop. You should try not to scratch the skin to prevent other infections and to ensure you can apply the treatment as soon as possible.

Other signs of possible pubic lice infestation include:
* skin which is redder than usual;
* what look like flakes of skin in your hair but are nits stuck to the hairs;
* black spots on your underwear due to louse droppings or blood spots;
* blue spots which are deep in the skin and don't go away if you press on them - these are from lice bites;

Complications of pubic lice
If the eyelashes are infected with lice, it can sometimes cause an eye infection called conjunctivitis. This needs separate treatment.

Causes of pubic lice
Lice are usually passed via sexual or intimate contact with somebody, as they crawl from hair to hair. It's also thought that they can live on bed sheets, towels or clothes briefly and occasionally be passed this way.

If you have genital contact with an infected partner but don't have sex, you can still get pubic lice. People who have more than one sexual partner or frequently change sexual partners are more at risk.

Diagnosis of pubic lice
If you think you may have pubic lice, you can visit your GP or a genitourinary medicine (GUM) or sexual health clinic. You can contact a GUM or sexual health clinic to make your own appointment. All visits are confidential and you don't have to give your real name. Details are not sent to your GP without your consent.

Tests may include a physical examination. Seeing the lice, eggs or blue spots is used to diagnose this condition.

If you have pubic lice, you may also have another sexually transmitted infection (STI) such as chlamydia. Swabs (to get cells or traces of infection) may be taken and you may be asked for blood and urine samples. The samples are used to test for other STIs at the same time.

Help and support
It may be difficult to come to terms with the diagnosis of pubic lice. Talking with the medical professional who treats you can be helpful.

Treatment for pubic lice
Treatment is with lotions or shampoos containing malathion (eg Derbac-M, Prioderm, Quellada M), permethrin (eg Lyclear) or phenothrin (eg Full Marks). All the body hair needs to be treated including your beard (if you have one) and eyebrows. The preparation is applied for 12 hours then washed off. You should re-apply the lotion or shampoo seven days later to ensure any lice which may have hatched after the last application, are also killed. Nits can be removed using a fine comb as they can stick to the hairs after treatment. Be careful not to get the lotion in your eyes. You shouldn't use this treatment on broken skin, or skin which has another type of infection. Children under 18 and breastfeeding and pregnant women should always seek medical advice first.

Eyelashes can be treated with permethrin in the same way using a cotton bud. An eye ointment or a paraffin-based product (eg Simple eye ointment BP, Larci-Lube, Lubri-Tears) may be advised. This treatment is applied twice a day for about eight to 10 days. Before applying the new ointment, the old ointment should be brushed away.

Ask your pharmacist for advice.

Lice can possibly live in bedding and clothing so these should be washed at a high temperature (50°C) or dry cleaned to kill the lice, preventing re-infection.

You might need to have repeat treatments to get rid of the lice as they can re-occur.

Treatments designed for removing head lice should not be used as they are too harsh for the genital area.

Prevention of pubic lice
Using condoms for vaginal, anal and oral sex can help prevent most sexually transmitted infections but can't protect you from getting pubic lice. Lice can live on bed sheets or clothes and occasionally be passed this way, so not sleeping in other people's bed may limit the risk of infection. Reducing the number of sexual partners reduces the risk.

If you have pubic lice, your current or most recent sexual partner may have them too and should be contacted to prevent them passing the infection to others. Clinics can send anonymous notifications on your behalf if you are willing to provide details.

People who are at increased risk of catching a pubic lice infection and other STIs, such as those who change sexual partners frequently, should consider having a check-up at the GUM clinic every few months. If you are diagnosed with pubic lice, you should wait until the doctor gives you the all clear before you start having sex again.

Pubic lice Q&As
See our answers to common questions about pubic lice, including:
* Have I got pubic lice because I haven't been hygienic?
* How do I tell the difference between head lice and pubic lice?
* My partner has just told me he has pubic lice and I should go get checked. What should I do?

Related topics
* Sexual Health Advice & Leaflets

Further information
* Sexual Health and National AIDS Helpline
0800 567 123;
* Condom Essential Wear
www.condomessentialwear.co.uk
* Sexually Transmitted Infections (STIs) - An Overview;

Sources
* Pattman RSM Handy P Sankar K N et al.Oxford handbook of genitourinary medicine, HIV and AIDS. Oxford: Oxford University Press, 2005;
* Pubic lice. Clinical Knowledge Summaries. www.cks.library.nhs.uk/pubic_lice, accessed 25/02/2009;
* Joint Formulary Committee, British National Formulary. 56th ed. London: British Medical Association and Royal Pharmaceutical Society of Great Britain, 2008;