Pediculosis pubis commonly called "crabs", is a disease caused by the crab louse an ectoparasite. Symptoms of crab louse infestation in the pubic area include itching, redness and inflammation. Other lice that infest humans are the head louse and the crab louse. Other lice that infest humans are the body louse and the crab louse. The crab louse can travel up to on the body. The crab louse can travel up to 10 inches on the body. The crab louse usually is found in the person's pubic hair.