Head lice

Alternative Names

Lice – head; Nits; Pediculosis capitis – head lice

Definition of Head lice

Head lice are tiny insects that live on the scalp. They can be spread by close contact with other people.

Causes, incidence, and risk factors

Head lice infect hair on the head. They are easiest to see on the neck and over the ears. Tiny eggs on the hair look like flakes of . However, instead of flaking off the scalp, they stay put.

Signs and tests

To see head lice, you need to look closely. Use disposable gloves and look at the person’s head under a bright light. Full sun or the brightest lights in your home during daylight hours work well. A magnifying glass can also help.

Treatment

Lotions and shampoos containing 1% permethrin (Nix) often work well. They can be bought at the store without a prescription. If these do not work, a doctor can give you a prescription for stronger medicine. Such medicine should be used exactly as directed.

Expectations (prognosis)

Lice are usually killed with proper treatment. However, lice may come back, especially if the source is not corrected. For example, a classroom with many infected children can cause kids to repeatedly get lice.

Review

Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc. – 1/29/2010

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

ADAM Medical Encyclopedia

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