Pediculosis

What is pediculosis?

Pediculosis is an infestation of the hairy parts of the body or clothing with the eggs, larvae or adults of lice. The crawling stages of this insect feed on human blood which can result in severe itching. Head lice are usually located on the scalp, crab lice in the pubic area and body lice along seams of clothing which travel to the skin to feed.

Anyone may become louse infested under suitable conditions of exposure. Pediculosis is easily transmitted from person to person during direct contact. Head lice infestations are frequently found in school settings or institutions. Crab lice infestations can be found among sexually active individuals. Body lice infestation can be found in people living in crowded, unsanitary conditions where clothing is infrequently changed or laundered.

For both head lice and body lice, transmission can occur during direct contact with an infested individual. Sharing of clothing and combs or brushes may also result in transmission of these insects. While other means are possible, crab lice are most often transmitted through sexual contact.

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

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

Pediculosis can be spread as long as lice or eggs remain alive on the infested person or clothing. What is the treatment for pediculosis?

Medicated shampoos or cream rinses containing lindane or pyrethrins are used to kill lice. Products containing pyrethrins are available over-the-counter, but those containing lindane are available only through a physician's prescription. Lindane is not recommended for infants, young children and pregnant or lactating women. Retreatment after seven to 10 days is recommended to assure that no eggs have survived. Nit combs are available to help remove nits from hair. 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. Health education on the life history of lice, proper treatment and the importance of laundering clothing and bedding in hot water (140°F for 20 minutes) or dry cleaning to destroy lice and eggs is extremely valuable. In addition, regular direct inspection of children for head lice, and when indicated, of body and clothing, particularly of children in schools, institutions, nursing homes and summer camps, is important.

New York State Department of Health