Crabs

Pubic lice (Phthirus pubis) are tiny parasitic insects that live on coarse human body hair, such as pubic hair.

They spread through close body contact, most commonly sexual contact. 

After you get pubic lice, it can take several weeks before symptoms appear. The symptoms include:

• itching in the affected areas
• inflammation or irritation in the affected areas caused by scratching
• black powder in your underwear
• blue-coloured spots on your skin where the lice are living, such as on your thighs or lower abdomen (these are caused by lice bites)
• tiny blood spots on your underwear or skin

Read more about the symptoms of pubic lice.

As well as being found in pubic hair, the lice are also sometimes found in:

• underarm and leg hair
• hair on the chest, abdomen and back
• facial hair, such as beards and moustaches
• eyelashes and eyebrows (very occasionally)

Pubic lice are sometimes called crab lice because they look similar to crabs. Adult lice are about 2mm long and are yellow-grey or dusky red in colour. The lice attach their eggs (or nits) to the base of hairs.

The lice do not transmit HIV or other sexually transmitted infections (STIs), but a sexual health check-up is always recommended if you have pubic lice.

Pubic lice are not the same as head lice and do not live in the hair on your scalp.

How do you get pubic lice?

Pubic lice are not linked to poor personal hygiene. They are spread through close body contact with someone who has them.

The lice crawl from hair to hair, but cannot fly or jump. They need human blood to survive, so generally only leave the body to move from one person to another.

They are most commonly passed on during sexual contact. Condoms will not prevent them being passed to another person.

It is also possible for pubic lice to be spread through sharing clothes, towels and bedding.

Read more about the causes of pubic lice.

When to seek medical advice

If you think you may have pubic lice, go to your GP or your nearest sexual health clinic, also known as a genitourinary medicine (GUM) clinic, for a check-up as soon as possible.

It is usually easy to diagnose pubic lice by examining the affected area. The doctor or nurse may use a magnifying glass to look for signs of the lice, such as pale-coloured eggs or the lice themselves.

If you have pubic lice as a result of sexual contact, you should be tested for other sexually transmitted infections (STIs).

Find your local sexual health services.

Treating pubic lice

You can treat pubic lice yourself at home by using a special type of lotion, cream or shampoo. Your doctor or pharmacist can advise you about which treatment to use and how to use it. It's important to follow this advice.

The treatment is applied to the affected area and sometimes the whole body. It usually needs to be repeated after three to seven days.

If the treatment doesn't work, you may need to use another type. This is because pubic lice can sometimes develop resistance to certain treatments. Your doctor or pharmacist can advise you on suitable alternatives.

It's also important to treat anyone you have had close body contact with, including current sexual partners and household members.

Read more about treating pubic lice.

Complications of pubic lice

A pubic lice infestation can sometimes lead to minor complications, including skin and eye problems.

Skin problems

If you have pubic lice, your skin may become irritated from scratching.

Scratching can cause scratch marks on your skin, or it could lead to an infection such as impetigo (a contagious bacterial skin infection) or furunculosis (boils on the skin).

Eye problems

Eye infections, such as conjunctivitis, and eye inflammation, such as blepharitis, can sometimes develop if your eyelashes have been infested with pubic lice.

See your doctor if your eyes become sore.