“She’s been sent home from school again — I’ve tried everything from the chemist and nothing works”

Persistent head lice are rarely due to “super-resistant” lice. Most treatment failures come from incorrect use (wet hair, too short a contact time, too little product), a missed 7-day repeat application, or reinfestation from untreated close contacts, often a second household. Take a precise treatment history and ask what else has been tried: parents under pressure sometimes use unsafe remedies such as veterinary insecticides, paraffin or undiluted essential oils. Stop them, wash the hair, and check for skin irritation and systemic symptoms (advice is available from NHS 111, or for clinicians through TOXBASE/NPIS). Diagnosis and cure are confirmed by detection combing for live lice. A physically acting product such as dimeticone 4% avoids insecticide resistance; it must be applied to dry hair over the whole scalp, left for the full time in the product information and repeated after 7 days (check the SPC/product information), with detection combing 2–3 days after finishing and again a week later. Structured wet combing is the alternative. Check everyone in each household the child lives in, and treat only those with live lice, on the same day. UKHSA guidance for schools and childcare settings sets no exclusion for head lice, so a GP can support the child’s return and raise any bullying with the school or school nurse. National self-care guidance means head-lice products are usually bought over the counter, but it allows prescribing where significant social vulnerability limits self-care. The skills are a non-judgemental treatment-failure analysis, spotting the safety issue, involving the child, and practical help across two households and the school.