What should you know about severe head lice?

Head lice are small insects that live close to the scalp and feed on blood. An infestation may cause itching, a crawling sensation, scratch marks or disturbed sleep; itching can be worse at night. Nits are eggs attached firmly to hair shafts, while dandruff usually brushes away more easily. Heavy scratching can irritate the skin and create open areas that may become infected. Finding a live crawling louse is more useful for confirmation than seeing an old nit alone. Head lice spread mainly through close head-to-head contact, so the person affected is not a sign of poor hygiene.

Arrange a clinical assessment or use a recommended lice treatment exactly as directed. Treatments may be lotion, liquid or another formulation, and some require a second application because eggs can survive the first treatment. Wet-combing with a fine-toothed comb can help remove lice and nits. Check household members and close contacts, but treat only people with confirmed live lice or advice from a clinician. Wash or isolate recently used pillowcases, hats and hair tools, and avoid sharing them. Do not use extra product, insecticide sprays or repeated applications outside the instructions. A GP consultation can help when the diagnosis is uncertain, the scalp is sore, or treatment has not worked.

Seek prompt medical advice for spreading redness, pus, marked swelling, fever, severe scalp pain or wounds that are not healing. Get advice if a young child, pregnant person or someone with a skin condition is affected, because product choice may need individual guidance. Arrange review when live lice remain after correctly following the full treatment plan, or when itching continues without any lice being found; another scalp condition may be responsible.

Ask whether live lice are present, which product suits the person's age and scalp, when it should be repeated, and how contacts should be checked. Ask how to care for scratched skin and when persistent itching needs another diagnosis.