What should you know about the most effective lice treatment?

Head lice live on the scalp and feed on blood. They spread mainly through close head-to-head contact, while nits attach firmly to hairs. Itching can continue briefly after live lice have been removed, so finding a moving louse is more useful than judging treatment by itch alone.

Products differ in which lice stages they affect and whether a repeat application is needed. Misidentifying dandruff or product residue as nits can lead to unnecessary treatment. [Head Lice](/conditions/head-lice/) and [Itchy Scalp](/symptoms/itchy-scalp/) provide related information.

Follow the chosen product’s directions exactly, including application time and any repeat dose. Use a fine-toothed nit comb on wet, conditioned hair, working in small sections from the scalp to the ends. Check close household contacts and treat only people with confirmed live lice or advice from a clinician. Wash or isolate recently used hair items, but extensive home fumigation is unnecessary.

Do not layer different lice products, apply them more often than directed, or use household chemicals. If live lice remain after correct use, a clinician can review application, reinfestation, and another treatment option. See [Head Lice Treatment](/treatments/medical-dermatology/head-lice-treatment/) for more detail.

Seek medical advice if the scalp has spreading redness, crusting, pus, marked swelling, or painful sores from scratching. Ask for help when a child is very young, the diagnosis is uncertain, or live lice remain after following directions. Seek urgent help for breathing difficulty or facial swelling after a product.

How can I confirm live lice? Which product suits this person’s age and scalp? When should I repeat it? How should I comb and check the hair? What should close contacts do?