Pubic lice (crabs)

Got Crabs?

Pubic lice

Crabs are often referred to as pubic lice and are not to be confused with body lice. The scientific name for crabs is Pediculus pubis. Crabs need blood to survive, but they can live up to 24 hours off a human body. Crabs have three very distinct phases; egg, nit, and adult louse. The louse is the stage of the parasite that causes itching.

How do you catch crabs?

You can get crabs when you have skin-to-skin contact with another person. You can get crabs from sleeping in an infested bed or using infested towels.


The most common symptom of crabs is itching in your pubic area. The itching is caused by an allergic reaction to the bites, and usually starts about five days after you get crabs. If you have crabs and look closely enough in your pubic area, you may see small crab-like parasites that may be whitish-gray or rust colored. Crab eggs are small and oval-shaped. They are attached to the base of the hair. You may see "blue spots" for several days; these are the result of the bites. Crabs are usually found in your pubic area; however, you may find them in your armpits, eyelashes, beard, mustache, and sometimes in the hair on your head.


There is a cream rinse, called premethrin, which you apply to the affected area and wash off after 10 minutes. Another option is lindane (also known as kwell). This is a shampoo that you leave on for four minutes then wash off. You will also need to wash and dry all your clothes, sheets, sleeping bags, etc. in hot water.

How can crabs be prevented?

  • Abstinence

  • having sex with only one uninfected partner

  • Limit the number of sex partners

  • Use latex condoms

  • Know your partner

  • Have regular check-ups if you are sexually active

  • If you have an STD, don't have sex until all partners have been treated.