When it happens · 4 min read
Head lice: the letter came home
A letter came home, or you spotted something while brushing their hair. It will happen, probably more than once, and it says nothing about your house, your child, or how often anyone washes their hair.
What is worth having is an accurate picture, because most of the work families put into head lice is spent on the parts that make no difference.
Last updated August 17, 2026
Finding them
Itching is unreliable. Many children never itch at all, and itching can carry on for a while after successful treatment, which sends people into a second and third unnecessary round.
The method that works is wet detection combing: conditioner on wet hair, then a fine-toothed lice comb through section by section, wiping the comb onto white tissue after each pass and looking at what comes off.
You are looking for live, moving lice. Eggshells cemented to the hair shaft well away from the scalp have already hatched and are not evidence of anything current. Only treat if you find a live louse — treating on suspicion is how resistance builds and how families end up treating repeatedly for nothing.
Treating them
Use a recommended treatment and follow its timing exactly, including the repeat dose. The repeat exists because the treatments do not reliably kill eggs; it catches what has hatched since, and skipping it is the single most common cause of failure. For the older pyrethrin products that is around nine to ten days after the first application.
Comb through afterwards to clear out what has been killed, and keep combing every few days for a couple of weeks to confirm it is actually gone.
Check everyone in the household on the same day, and treat only the ones with live lice.
If a treatment genuinely fails despite being used correctly, ask rather than repeating the same product. Resistance to the older treatments is well documented and there are alternatives.
What isn't worth doing
Deep-cleaning the house. Lice die within a day or two away from a scalp. Washing recently used bedding and hats is plenty; bagging up soft toys for weeks and hiring carpet cleaners is not.
Keeping a child off school. Head lice do not justify exclusion, and no-nit policies are not supported by the medical guidance.
Smothering hair overnight in mayonnaise, petroleum jelly or anything flammable. Messy, largely ineffective, and in the case of anything flammable, genuinely dangerous.
Telling anyone off. It spreads through head-to-head contact between children who are playing properly, which is what you want them doing.
Common questions
- There are still eggs stuck to the hair after treatment. Did it work?
- Probably. Empty eggshells stay glued to the hair as it grows out and can sit there for months. What matters is whether wet combing turns up live, moving lice.
- Do I need to treat everyone in the house?
- Check everyone on the same day, but treat only those who actually have live lice. This is the opposite of the advice for pinworms, where the whole household is treated together.
- Can they go to school?
- Yes. Exclusion is not recommended and has no effect on spread, since by the time lice are found they have usually been there for weeks.
If it's this, not that
Still not sure
This page is the general answer. Yours is a specific child.
The advisor can be. It has read everything here, and it knows how old your children actually are — which is the whole difference wherever guidance changes with age. Ask it anything.
- She's got a temperature of 100. Is that something to worry about?
- He's obsessed with space and galaxies — what toys are worth getting him?
Free. It comes with the note.
It answers from the same cited pages you are reading, and when the question is where to go, from the real clinician, hospital and childcare records behind this site — not a link to go search them yourself. It says so when we have not written about something, and it is not a doctor; for anything urgent it gives you the threshold and tells you to call.
Where this comes from
- Signs of lice, and how to check for themAAP
- Treating head lice - the repeat dose, and the cleaning that isn't neededCDC
Every claim on this page traces to one of these. See every source we use →
Written from the sources named above, and it is not a substitute for your own doctor. If something feels wrong to you, that instinct is a good enough reason to call — you know yourself and this family better than any page does.