Head lice

Injury	Disease	Nutrition	Poison

Symptoms	Surgery	Test	Special Topic

Head lice

Nit on human hair

Lice, head - nits in the hair with close-up

Head louse emerging from egg

Head louse, male

Head louse - female

Head louse infestation - scalp

Head lice

Definition:

Head lice are tiny insects that live on the scalp. They can be spread by close contact with other people.
Alternative Names:
Lice - head; Nits; Pediculosis capitis - head lice
Causes, incidence, and risk factors:

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There are three common types of lice: head lice, body lice, and pubic lice (also called crabs). Head lice infect the scalp hair and are easiest to see at the nape of the neck and over the ears. Tiny eggs can be seen on the hair, appearing much like flakes of dandruff, but stuck firmly to the hair shaft instead of flaking off the scalp.

Lice can also live on clothing, carpets, or bedding.

Head lice are spread easily and cause intense itching, but they do not lead to a serious medical problem. Lice are more common in close, overcrowded living conditions. Lice spread readily among school children.

Having lice is NOT an indicator of poor hygiene or low social status.

References:

Long SS, Pickering LK, Prober, CG, eds. Principles and Practice of Pediatric Infectious Diseases. 2nd Ed. New York, NY: Churchill Livingstone, 2003.

Mandell GL, Bennett JE, Dolin R, eds. Principles of Infectious Diseases. 5^th Ed. New York, NY: Churchill Livingstone, 2000:2972-2973.

Goetz CG, Pappert EJ. Textbook of Clinical Neurology. 2^nd Ed. Philadelphia, PA: Saunders; 2003.