Head lice
Head lice are insects that live on the scalp and feed on blood. They are very common in school-age children and have nothing to do with cleanliness — if…
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Medicines commonly prescribed for Head lice
For informational purposes only. Always consult a doctor before using any medicine.
Dosage form: CREAM, 5 g permethrin / 100 gActive substance: permethrinManufacturer: Unipharma S.A.Prescription requiredDosage form: CREAM, 5 g permethrin / 100 gActive substance: permethrinManufacturer: Galenicum Derma S.L.U.Prescription required
Head lice are insects that live on the scalp and feed on blood. They are very common in school-age children and have nothing to do with cleanliness — if anything they hold on better to clean hair. They do not transmit disease. What usually fails is not the product but the way it is applied and the lack of a second treatment a few days later.
How to recognise them
- an itchy scalp, particularly behind the ears and at the nape; in a first infestation it can take weeks to start;
- a sensation of movement in the hair;
- small sores and crusts from scratching;
- nits: oval, whitish or brown eggs firmly glued to the hair near the root. They do not blow off or shake out like dandruff;
- adult lice: the size of a sesame seed, grey or brown, moving quickly and avoiding light;
- enlarged lymph nodes at the nape in long-standing infestations;
- disturbed sleep from night-time itching.
The diagnosis is made by finding a live louse, not nits alone: white nits sitting well away from the root are usually the remains of an infestation already treated.
How to look properly
Wet combing is the most reliable method, and it costs nothing.
- apply plenty of conditioner to wet hair: it immobilises the lice;
- detangle with an ordinary comb;
- comb section by section with a fine-toothed metal nit comb, from the roots to the ends;
- wipe the comb on a white tissue after each stroke and look at what comes off;
- work through the whole head systematically, in good light;
- it takes 10–15 minutes and finds what the eye cannot.
How they spread
- direct head-to-head contact — by far the main route;
- shared hats, scarves, helmets, headbands and hair ties;
- combs and brushes;
- pillows and headrests, though the risk is much lower;
- they do not jump or fly: they only crawl;
- away from the head they survive one to two days.
Treatment
- dimeticone lotions — the first choice today. They work physically, by suffocating the louse, so resistance does not develop;
- permethrin and other insecticides — still effective in many areas; if they do not work, switch to a different mechanism rather than repeating the same product;
- apply to dry hair unless the leaflet says otherwise, covering the whole scalp and all the way to the ends, without skimping on quantity;
- observe the stated contact time: this is where most people go wrong;
- repeat after 7–9 days: this is essential. No product kills all the eggs, and the second treatment eliminates those that have hatched. Skipping this step is the number one reason for "they always come back";
- comb with a nit comb every 3–4 days for two weeks, even if you have used a product;
- check everyone in the household on the same day and treat only those with live lice;
- for resistant cases, oral treatments are available on prescription.
The home
Far more is usually done here than is necessary. Lice do not live in furniture.
- wash bedding, towels and hats used in the last two days at 60 °C;
- anything that cannot be washed can go in a sealed bag for three days;
- soak combs and brushes in hot water for 10 minutes;
- vacuum sofas and car seats for peace of mind rather than necessity;
- there is no need to fumigate the house or throw away soft toys.
When to see a doctor
- two correct treatments have not worked;
- the scalp is red, with yellow crusts, pus or tender lymph nodes — bacterial infection;
- intense itching persists after the lice have gone;
- it is a baby under two, or you are pregnant or breastfeeding: products are chosen carefully;
- there is an allergy to any of the ingredients;
- you are unsure whether what you see is nits or dandruff;
- there are lice on the eyelashes: these are treated differently and never with these products.
Common questions
Should the child stay off school? No. Treat on the same day and the child can continue attending. Telling the school does help break the chain.
Do oil, mayonnaise or vinegar work? Vinegar may help loosen nits but does not kill lice. The rest has no proven effect.
Does the hair need cutting? No. Long hair only makes combing more laborious.
Do repellents prevent them? Their effectiveness is limited. What actually works is tying hair back, not sharing hats or brushes, and weekly nit combing.
Can they come from a dog or cat? No. Head lice live only on people.
Online consultation
In an online consultation the doctor helps confirm whether these are lice or dandruff, reviews how you applied the treatment — quantity, contact time and second dose — chooses a suitable product if the previous one failed, takes account of age and pregnancy, and recognises signs of scalp infection.
This material is for information only and does not replace a medical consultation.
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Reviewed on Jul 11, 2026
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