Crab lice are small insects that live in coarse body hair (pubic, underarm and on hairy legs and chests). They have also been found in beards and eyelashes.
Sexual contact is the most common way they are spread, although they may be transferred via other types of body contact. It is occasionally possible for them to be spread by clothing or bedding.
Lotions and shampoos are available to kill the crabs and their eggs. A lotion is applied to the skin, especially the hairy areas, and left on for 12 hours before washing off. This can be repeated one week later. If using shampoos, carefully follow your doctor's advice and the instructions on the pack.