Head Lice & Crabs

Humans are commonly infected with several different species of lice. These parasites live on human blood and do not infect other species. Each type of lice prefers a different area of the body.

Types

• Head lice, or Pediculus humanus capitis, infects only the hair and scalp. Pubic lice, otherwise known as Pthirus pubis or more commonly known as crabs, infects only the pubic area. A third type of lice, called the body or clothes louse---formally, Pediculus humanus corporis---feeds on the rest of the body, according to the Centers for Disease Control and Prevention.

Transmission and Symptoms

• EMedicine explains that head lice is a common infestation. Anyone can get head lice, regardless of their socioeconomic status or level of personal cleanliness. Head lice is often characterized by scalp itchiness. Crabs are spread through sexual contact and cause intense itching and bluish sores in the pubic area.

Risk Factors

• Children between 3 and 10 years of age are more likely to become infested with head lice than other populations, and girls are more likely to be infected than boys. Pubic lice affects sexually active adults and may accompany other sexually transmitted diseases, according to EMedicine.