Intended for healthcare professionals

Clinical Review Extracts from “BestTreatments”

Treating head lice

BMJ 2003; 326 doi: (Published 05 June 2003) Cite this as: BMJ 2003;326:1256
  1. Beth Nash1, physicians editor, BestTreatments (
  1. BMJ Publishing Group, London WC1H 9JR


    Description Head lice are parasites that usually infest the scalps of school age children, although adults also get them. Lice attach their eggs to hair shafts near the scalp and lay five to six eggs a day. Lice never willingly leave the head; they stay close to the scalp for food, shelter, warmth, and moisture. They are most often found behind the ears and at the back of the neck. Hatched eggshells (nits) may be confused with dandruff. The mature louse is the size of a sesame seed and has six legs and hook-like claws that grasp the strand of hair tightly, making it difficult to dislodge. It feeds on the host's blood every three to six hours, which can cause scalp itching, though most cases are asymptomatic. The diagnosis of lice infestation can be made definitively only if living lice are present.

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    Treatments that are likely to work


    Malathion works as well as other agents used to kill lice. Malathion must be left on for at least eight hours for it to work. It is applied to dry hair …

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