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Head Lice

Head Lice (Pediculosis)

(peh-DICK-you-LO-sis)

Adult head louse

An adult head louse. (CDC Photo)

Adult head lice are 2.1-3.3 mm in length. Head lice infest the head and neck and attach their eggs to the base of the hair shaft. Lice move by crawling; they cannot hop or fly.

Head lice infestations are spread most commonly by close person-to-person contact. Dogs, cats, and other pets do not play a role in the transmission of human lice.

Both over-the-counter and prescription medications are available for treatment of head lice infestations.

Specific Topics

Information for Special Groups and Settings

Head Lice Resources

Page last modified: May 16, 2008
Page last reviewed: May 16, 2008
Content Source: Division of Parasitic Diseases (DPD)
National Center for Zoonotic, Vector-Borne, and Enteric Diseases (ZVED)