Crab louses are tiny parasites that infest the human body and cause extreme itching and discomfort. Synonyms for crab louses include pubic lice, crabs, and genital lice. These parasitic insects attach themselves to hair follicles in the genital area and feed on human blood. They spread through close contact such as sexual contact or using infected bedding or towels. Infected individuals may experience skin irritation, redness, and inflammation. To treat crab louse infestations, doctors may prescribe medicated lotions or shampoos. Prevention methods such as practicing safe sex and avoiding sharing towels and bedding can also be effective in avoiding infestations of crab louses.