Pubic lice (crabs) - including symptoms, treatment and prevention

Public lice is an infestation of the pubic hair by the pubic or crab louse, Pthirus pubis. In heavy infestations they may be found in other hairy parts of the body, especially the armpits and eyebrows. They are different from head lice.

How pubic lice are spread

Transmission is mostly through direct skin-to-skin contact during sexual activity, but they can be spread on bedding, clothing or by close non-sexual body contact.


The main symptom is itching in the genital area.


The diagnosis is made on careful inspection of the affected area, as the lice can be seen by the naked eye.

Incubation period

(time between becoming infected and developing symptoms)

The eggs usually hatch in 7 days and adult lice live for about 30 days. It may take up to 1 month for symptoms to develop, as the person develops an allergic reaction to the saliva injected by the louse when biting.

Infectious period

(time during which an infected person can spread the lice to others)

While there are living adult lice the lice can be passed on.


Insecticidal creams and lotions may be obtained from pharmacies. They should be used strictly according to directions and treatment repeated after a week to kill any lice that may have hatched since the first treatment. They should not be used around the eyes. This area may be treated with petroleum jelly twice a day for 8 days. Consult your doctor for treatment of severe itching or if the bites become infected.


  • Any sexual partners you have had over the past month need to be examined and treated for pubic lice.

  • Avoid close personal contact until you and infected partners have completed treatment.

  • Condoms do not protect you against pubic lice.

  • Wash bedding, all clothing including night clothes and bath towels used while infestation was present in hot, soapy water, or dry clean.

  • Testing to exclude other sexually transmitted infections is advisable.

  • Get tested for sexually transmitted infections regularly (even if you do not have symptoms), particularly when you have new sexual partners.

Useful links