Crab lice are small, light brown, flat, pinhead insects that infest pubic hair.
Although usually transmitted through sexual contact, crab lice infestation may also be caused by sleeping in a bed or sharing the towels or clothing of an infested person. The lice can remain alive in bedding for 1 to 2 weeks. Crab lice do not leave the body voluntarily and must be treated. Apply the lice-killing shampoo to the pubic hair. Make sure all the hair is wet with the product.