Pubic lice (phthirus pubis), also known as crabs, are tiny blood-sucking insects. They live in coarse human body hair, most commonly pubic hair, and cause itching and red spots.

The lice can also be found in:

• the eyelashes or eyebrows

• hair on the abdomen or back

• facial hair, such as beards or moustaches

Adult pubic lice are about 2mm long and are grey-brown in colour.

Pubic lice are caught through close contact with someone who has them. The most common way is during sexual contact. There is not enough evidence to say whether pubic lice can be transferred through items such as bedding or towels, although some experts think that it might be possible.

How common are pubic lice?

In 2006, the last year for which figures are available, there were 2,500 cases of pubic lice seen at sexual health (also known as genito-urinary medicine or GUM) clinics in the UK.

Pubic lice only affect humans and do not live on other animals. They can affect people of any age, but are most commonly found in young adults.

Outlook

The outlook is generally good. Pubic lice can usually be successfully treated with insecticide medicines available over-the-counter (OTC) in most pharmacies, or from a GP or GUM clinic. If pubic lice were caught through sexual contact, any current sexual partners and partners from the previous three months may need to be informed and treated.

If pubic lice are caught through sexual contact, it is recommended that tests are also done for other sexually transmitted infections (STIs).