Head Lice

Head lice are tiny insects. The crawling stages of this insect feed on human blood which can result in severe itching. Head lice can be found anywhere on the scalp but are heaviest behind the ears and just above the hairline along the nape of the neck. Head lice attach their eggs (nits) to human hair.

Disease Fact Sheet

Disease Facts

Anyone may become infested with head lice under suitable conditions of exposure. Lice are easily transmitted from person to person during direct contact. Head lice infestations are frequently found in homes, day care, school settings or institutions.

Head lice transmission can occur during direct contact with an infested individual. Head lice cannot jump or fly. Head to head contact or sharing items of clothing, combs, brushes, hats, or headphones may also result in transmission. Shared surfaces such as pillows, mattresses, sleeping bags, cars seats or upholstered furniture may also transmit head lice.

Usually, the first indication of an infestation is the itching on the head. Scratching at the back of the head or around the ears should lead to an examination for head louse eggs (nits) on the hair. Scratching can be sufficiently intense to result in secondary bacterial infection in these areas.

It may take as long as two or three weeks or longer for a person to notice the itching associated with head lice.

Head lice can be spread as long as lice or eggs remain alive on the infested person.

Medicated shampoos or cream rinses containing pyrethrin (Rid), permethrin (Nix), lindane (Kwell) or malathion (Ovide) are used to kill lice. Products containing lindane or malathion are available only with a physician’s prescription. Lindane is not recommended for infants, young children and pregnant or lactating women. Lindane is banned in California. If a lindane or pyrethrin product is used, retreatment after seven to 10 days is recommended to assure that no eggs have survived. If a permethrin product, such as NIX is used, retreatment is not necessary because there is a residual chemical effect for about two weeks. Nit combs or solutions to soften nit glue are available to help remove nits from hair. It is very important that dose and duration of shampoo treatment should be followed according to label instructions.

Physical contact with infested individuals and their belongings, especially clothing, headgear and bedding should be avoided. Check the heads of household members and treat those found to be infested. Thorough cleaning should be done of household items including: vacuuming upholstered furniture and carpet; laundering clothing and bedding in hot water (130° F for 20 minutes) and drying on hot cycle or dry cleaning to destroy lice and eggs; soaking combs and brushes in hot water (130° F for 10 minutes). Anything that cannot be laundered should be sealed in a plastic bag for two weeks. Educate persons involved on the transmission and the treatment of head lice. Where large scale infestations involve several families, the importance of coordination of treatment and prevention efforts is important.

Related Sites

  • American Academy of Pediatrics 
    • Clinical report clarifying protocols for diagnosis and treatment, and provides guidance for the management of children with head lice in the school setting


This material is provided by the South Dakota Department of Health for informational purposes only and is not a substitute for medical care. We are not able to answer personal medical questions. Please see your health care provider concerning appropriate care, treatment, or other medical advice.

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