Treatment of head lice

Wet combing can be used to treat head lice; however, this method only has about a 40% success rate when used alone. Repeat wet combing daily until lice are not found. Combing is easier with shorter hair styles, but shaving the head is not necessary.

Two types of topical treatment are available for head lice: physical (occlusive) insecticides (eg benzyl alcohol, dimeticone, isopropyl myristate) and neurotoxic insecticides (eg malathion, pyrethrins+piperonyl butoxide). Physical methods work by physical mechanisms (eg occlusion of the louse respiratory system and disrupting water balance). Neurotoxic insecticides work by affecting the nervous system of the louse. There is no evidence of difference in efficacy between physical and neurotoxic insecticides.

For topical treatment of head lice, useBurgess, 2015Flores‐Genuino, 2020:

Various commercially available products are marketed for the treatment of head lice; however, some do not contain one of the insecticides listed above. There is insufficient evidence to recommend essential oils or ‘natural products’ for treatment of head liceBurgess, 2015.

Use the wet combing method the day after each treatment to check for live lice. If live lice are found despite treatment that has been correctly applied, the head lice are resistant to the product used—see Lack of response to treatment of head lice.

In between treatments, use the wet combing method twice, removing all eggs less than 1.5 cm from the scalp with the fine-toothed comb or by pulling them off with fingernails. The presence of eggs more than 1.5 cm from the scalp indicates previous, not active, infestation.

Wet combing should be repeated weekly for several weeks after cure to detect recurrence.

Wash pillowcases on a hot cycle, and combs and brushes in hot water (60°C).

To prevent recurrence of head lice, children should avoid sharing hats and hair accessories (eg hair elastics, brushes), and avoid playing with each other’s hair.