Lice

Lice Infestation

Lice are barely visible wingless insects that spread easily from person to person by body contact and shared clothing and other personal items. Three species of lice inhabit different parts of the body.

Head lice infest the scalp hair. The infestation is spread by personal contact and possibly by shared combs, brushes, hats, and other personal items. Head lice are a common scourge of school children of all social strata. Head lice are less common among blacks.

Body lice usually infest people who have poor hygiene and those living in close quarters or crowded institutions. They live in the seams of garments that are in contact with the skin.

Symptoms and Diagnosis

Lice infestation causes severe itching in the infested area. Intense scratching often breaks the skin, which can lead to bacterial infections. Children may hardly notice head lice or may have only a vague scalp irritation.

Lice themselves are sometimes hard to find, but their eggs are readily apparent. Female lice lay shiny grayish white eggs (nits) that can be seen as tiny globules firmly stuck to hairs near their base. With chronic scalp infestations, the nits grow out with the hair and therefore can be found some distance from the scalp, depending on the duration of the infestation.

Nits are distinguished from other foreign material present on hair shafts by the fact that they are so strongly attached. Adult body lice and their eggs also may be found in the seams of clothing worn close to the skin.

Treatment

Several effective prescription and nonprescription drugs are available to treat lice. Nonprescription shampoos and creams containing pyrethrins plus piperonyl butoxide are applied for 10 minutes and are then rinsed out. Prescription permethrin, applied as a liquid or as a cream, is also effective.  All louse treatments are repeated in 7 to 10 days to kill newly hatched lice.

After a drug application, nits must be removed manually, because drugs do not kill all nits and because it is not possible to distinguish between living and dead nits. Removal requires a fine-tooth comb—which is often packaged with the medication—and careful searching (hence the term "nit-picking"). Because the nits are so strongly stuck to the hair, several nonprescription preparations are available to loosen them.

The nits of body lice are destroyed simply by throwing away infested clothing.
Sources of infestation (combs, hats, clothing, and bedding) should be decontaminated by laundering or dry cleaning.




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