School starts this week or next for most of you, which means somewhere in America a school nurse is already reaching for the phone.

I have been that parent. I have also, at this point, talked to enough school nurses to know that lice season arrives on a schedule you could set a watch to. Late August. Every year. Like clockwork, but itchier.

So here is the whole Nit Happens lineup, laid out the way you'd actually use it rather than the way a catalog would list it. And because a product roundup that isn't useful is just an ad with better manners, I've put the actual guidance in here too. Steal it. Send it to the group chat. You don't have to buy anything for it to work.

First, the thing nobody tells you: your kid does not have to come home

The American Academy of Pediatrics updated its guidance in 2022 and was unusually blunt about it. Children with head lice should not be sent home early or kept out of school. Lice are not a health hazard, they're not a sign of poor hygiene, and by the time anyone notices them the kid has usually had them for weeks. "No-nit" policies do more harm than good, mostly to the kid's attendance record and dignity.

The only area I disagree with the AAP is "children should not be sent home early" - that does not acknowledge the reality that I'm familiar with. Your child is probably stressed and uncomfortable and probably attracting unwanted attention from classmates and their teacher. Better to pick up, treat, and try again tomorrow.

If your school still enforces a no-nit policy (I'm looking at you daycares), the AAP's report is the thing to bring to that conversation. Print it out. Be the parent with the receipts. It's very satisfying.

Step one: before it happens. School Day Spray (4 oz and 8 oz, from $14.99)

What it's for: every morning, on the way out the door. It's a detangler made with ingredients that lice don't care for. Orange peel extract, tea tree, lavender. It smells good, it gets the tangles out without the daily hairbrush negotiation, and with ingredients tested in the lab to repel lice.

What I'm not going to tell you: that it's a force field. It's a useful cosmetic, not a vaccine tested in a school. Nothing you spray on a kid's head makes lice impossible. What it does is make your kid's head a less appealing place to move to, and it gets the daily comb-through to actually happen, which matters more than people think, because you cannot find lice on hair nobody ever combs.

The rest of the prevention list, which is free

Lice do not jump and they do not fly. They walk, and they need hair touching another head to get anywhere. Almost everything that works follows from that one fact.

• Hair up on school days. Ponytail, bun, or braid, and a braid beats a ponytail because there's less loose hair swinging around. A bun is the best of the three for the same reason. Long loose hair is a mop, and kids put their heads together constantly: selfies, reading corners, the bus seat, the floor at assembly.
• Braid over the spray if you have to pick one. Do both if you can. The spray is the thing you'll actually remember because it's a detangler you were going to use anyway, and that's most of why it works.
• No sharing hats, helmets, hair ties, brushes, or headphones. The CDC's list, and the one kids ignore hardest. Bike helmets and dress-up bins at school are the two everybody forgets. Say this "what goes in the hair, we do not share" until everyone gets it.
• Backpacks and coats. If your school hangs everything on a shared hook or piles coats in a cubby, ask about giving each kid their own hook or a bag for their hat. Nurses have usually been asking for this for years and would love the backup.
• Sleepovers and camp are the two big ones. That's head-to-head contact for eight hours. Check on the Sunday after, every time.
• Skip the folk remedies. Vinegar rinses, mayonnaise, olive oil, furniture sprays. The CDC says plainly that it has no scientific evidence that smothering lice with mayonnaise, olive oil, margarine, or butter works, and the AAP's list of things to avoid entirely includes acetone, bleach, vodka, roach spray, and WD-40, which people have genuinely tried on their children's heads.

Step two: the check. The lice comb (it's in the kit, and it's the most important thing in the box)

Here's the one that changes outcomes, and it's free: check every Sunday during lice season. Two minutes. Wet hair, conditioner in it, fine-toothed comb, bright light, wipe the comb on a white paper towel after every pass.

Wet, conditioned hair is the whole trick. Lice can't grip and can't run in it, and conditioner makes the comb glide instead of catching.

What you're looking for:

• Nits are teardrop-shaped, glued to one side of the hair shaft, and they do not slide off. Dandruff slides off. If it slides, it's not a nit.
• Position tells you if it's active. Per the CDC, nits glued within about a quarter inch of the scalp mean a live infestation. Nits further out than that are almost always already hatched or dead, and they've just grown out with the hair.
• Don't wait for itching. The AAP notes that with a first case, itching may not show up for four to six weeks, because it's an allergic reaction that takes time to build. By the time your kid is scratching, this has been going on for a month. On a repeat infestation the itch comes fast, so a quick itch doesn't rule it out either.

Sunday night, two minutes, wet hair. That's the whole protocol. It catches things at four lice instead of four hundred.

Step three: the night it happens. Nit Happens Complete Lice Treatment Kit ($34.99, and it's at Walgreens tonight)

What's in it: treatment gel, removal shampoo, applicator brush, the comb, gloves, instructions.

What it does: it works by physical removal. The gel loosens the glue holding nits to the hair shaft so the lice and the eggs comb out. There's no pesticide in it, because pesticides have a problem I'll get to in a second.

The numbers, all of them. In our clinical study, 26 participants, IRB approved by IntegReview, run by independent investigators Maria Elena Villar and Susan Rubio Rivera: after one treatment at day 8, 54% were lice free. After the full protocol at day 15, 89% were lice free. Among the families who completed the protocol as written, 95.8%, or 23 of 24.

One participant out of 26 was a flat treatment failure. Nothing works on everyone. Anyone telling you their product does is selling, and I'd rather you hear that number from me than find it later.

Zero adverse events across the study. Separately, a dermatologist-controlled patch test at Evalulab in Quebec put it on 27 adults for 48 hours and every single one scored zero on the irritation scale. No alcohol in it, anywhere, which is the reason it doesn't sting a scalp your kid has already scratched raw.

The study hasn't been published in a peer-reviewed journal yet. We're preparing it for submission. Until it clears that bar, it's a real study with a real ethics review that hasn't been peer reviewed, and I'd rather write that sentence myself than let the word "clinical" do vague work.

About the drugstore pesticide kits. This isn't a shot at a particular brand, it's just what happened. A study in the Journal of Medical Entomology looked at 14,281 lice from 138 sites across 48 states and found a mean knockdown resistance frequency of 98.3%. In 42 of the 48 states, it was 100%. Exactly one collection site in America came back clean, in Frankenmuth, Michigan, which I think about more than is normal. The AAP puts it in plainer terms: effectiveness of those products has fallen from near 100% when they launched in the 1980s to as low as 25%.

So when you do everything on the box and find live bugs four days later, that isn't you. You applied a chemical the local lice are largely built to survive.

Step four: a week later, whether or not you want to

Do the second application. Look at the gap between 54% and 89% again. That gap is eggs. No treatment reliably handles every egg, which is why the second pass exists: it catches whatever hatched after the first one.

Each application takes about 50 minutes, most of it combing, and I'm not going to pretend that's a fun Tuesday. Put on a movie. It's still faster than doing this a third time in October.

Step five: the part everyone over-does

Wash the sheets and the pillowcases in hot water, and the hat and the car seat headrest if you want to feel thorough. Then stop.

Lice die within about 24 to 48 hours off a human head. They cannot live in your carpet, your couch, or your child's stuffed rabbit for weeks. You do not need to bag the toys, rent a steam cleaner, or burn the house down, and I say that as someone who once considered it.

What I'd tell you if we were in your kitchen

One. Check on Sundays. Everything else on this list is downstream of that.

Two. If your kid has eczema or reactive skin, patch test first, on the forearm, ten minutes, and check it again the next day and the day after. That goes for any brand. We wrote a whole page on lice treatment and eczema, including what our safety testing does and doesn't cover, because the honest answer has more limits in it than a product page usually admits.

Three. Tell the parents of whoever your kid had a sleepover with. I know yikes. Do it anyway. Lice move by head-to-head contact, so the sleepover is almost always the answer, and every parent who finds out late is a parent who does this twice.

Four. Your kid did nothing wrong and neither did you. Lice have no opinion about how clean your house is. The AAP is explicit that they aren't a sign of poor hygiene and don't spread disease. They're a nuisance with excellent PR.

Where to get it

• Nit Happens Complete Lice Treatment Kit, $34.99. At approximately 6,000 Walgreens stores nationwide, on Amazon, and at gocartwheel.com. If you need it tonight rather than Thursday, the store locator will tell you which Walgreens or independent pharmacy near you has it on the shelf.
• Nit Happens School Day Spray, 4 oz and 8 oz, from $14.99.

Good luck out there. Check on Sunday.

Sources: AAP clinical report on head lice, Pediatrics 2022;150(4):e2022059282. CDC head lice guidance. Gellatly et al., Journal of Medical Entomology 53(3), 2016 (samples collected 2013 to 2015). H.A.L.T. clinical study, Villar and Rubio Rivera, IRB approved by IntegReview, n=26. Dermatologist-controlled safety study 20H-0224-34, Evalulab, Quebec, n=27. Nothing here is medical advice. If your child has broken skin, an active scalp condition, or you're unsure, call your pediatrician.

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