Head lice are common in school-age children and have nothing to do with how clean someone is. They spread through head-to-head contact. They’re a nuisance but don’t carry disease, and most cases clear with one over-the-counter treatment plus combing.
How to check for head lice
- Look for live lice: small greyish-brown insects about the size of a sesame seed, moving close to the scalp.
- Look for nits (eggs) firmly stuck to hairs within about 6 mm (¼ inch) of the scalp, especially behind the ears and at the nape of the neck. Unlike dandruff, they don’t brush off easily.
- The most reliable way to check is wet combing: wet, conditioned hair combed section by section with a fine-toothed lice comb.
Only treat if you find a live louse. Nits alone may be old, empty shells.
Over-the-counter treatments compared
- Ivermectin 0.5% lotion (Sklice): applied to dry hair for 10 minutes, then rinsed. Usually one application is enough and nit-combing isn’t required. For ages 6 months and over.
- Permethrin 1% (Nix): applied to freshly washed, towel-dried hair without conditioner for 10 minutes, then rinsed. Repeat on day 9. For ages 2 months and over.
- Pyrethrins with piperonyl butoxide (Rid): applied to dry hair for 10 minutes, then repeated 7–10 days later. For ages 2 and over. Avoid if you’re allergic to ragweed or chrysanthemums.
In many parts of the US, lice have become resistant to permethrin and pyrethrins. If one of these hasn’t worked after two correct treatments, try a different type rather than repeating it.
Tips for treatment that works
- Follow the label exactly. Use enough to soak all the hair and the scalp.
- Don’t use conditioner or a combined shampoo-conditioner before permethrin, because it coats the hair.
- Comb with a lice comb every 2–3 days for 2 weeks to catch any lice that hatch.
- Check everyone in the household, but only treat those with live lice.
- Never use flammable products such as kerosene or petrol on the hair.
Cleaning at home
Lice die within 1–2 days off the scalp, so a big clean-up isn’t needed. Wash pillowcases, hats and towels used in the last 2 days in hot water (at least 130°F / 54°C) and dry on high heat, or seal items in a plastic bag for 2 weeks. Soak combs and brushes in hot water. Insecticide sprays for the home aren’t needed.
Can my child go to school?
The American Academy of Pediatrics advises that children don’t need to miss school because of head lice. They can go back after the first treatment.
See a doctor if
Lice keep coming back after two different treatments, the scalp looks infected (crusting, oozing, swollen glands), or the child is under 2 months old. Prescription options include spinosad and malathion.
Read more about ivermectin and its uses.
More in our Lice and Parasites guide: all our articles on this topic in one place.
This article is for general information only and isn’t a substitute for advice from a doctor or pharmacist. Always read the label before using any medicine.
