Head lice spread almost exclusively through direct head-to-head contact, which means prevention comes down to reducing hair-to-hair touching and properly handling items that have been near an infested person’s head. Lice cannot jump or fly. They crawl, and they need a human scalp to survive. Adult lice die within two days of falling off a person, and their eggs die within about a week without the warmth of a scalp. That short survival window works in your favor when you act quickly.
How Lice Actually Spread
Understanding the mechanics makes prevention much simpler. Lice move by crawling from one strand of hair to another, which requires close physical contact. This is why outbreaks happen among young children: they play closely together, share headphones, and huddle over screens. Indirect spread through shared hats, brushes, or pillows is possible but far less common than direct contact. The two-day survival limit off a human host means that objects sitting untouched for even a couple of days are very unlikely to be a source of new infestation.
Keep Hair Contained
Loose, flowing hair gives lice the easiest path to crawl from one head to another. Pulling hair back into a tight style significantly reduces that risk. A simple ponytail helps, but if you or your child has thick or bushy hair, a ponytail alone can still leave enough loose strands to create contact. Braids are a better option because they keep hair compact and close to the head. French braids, double Dutch braids, fishtail braids, and rope twists all work well. During an active outbreak at school or camp, braiding hair each morning is one of the simplest and most effective things you can do.
Check Everyone in the Household
When one person in your home has lice, check every household member within the first day or two. The most reliable method is wet combing with conditioner: apply a thick layer of conditioner to damp hair, then comb through small sections with a fine-toothed lice comb. This technique is about 1.25 times more accurate than dry combing and roughly 2.5 times more accurate than just looking with your eyes. The conditioner slows the lice down and makes them easier to spot on the comb’s teeth.
Wet combing is especially important for people with dark or brown hair, where visual inspection alone misses significantly more cases. Repeat the check every few days for two weeks, since eggs can take 7 to 10 days to hatch and a new case might not be obvious right away.
Handle Bedding and Clothing Quickly
Strip all bed linens (sheets, pillowcases, blankets) from the infested person’s bed and wash them on the hottest water setting your fabric can handle. Dry everything in the dryer on the hottest setting as well. The heat from the dryer is what actually kills lice and eggs reliably. For clothing, gather anything worn within the past 24 hours and run it through the same hot wash and dry cycle.
Items that can’t be washed, like decorative pillows or stuffed animals, can go in the dryer on the hottest temperature for 20 to 30 minutes. If an item can’t go in the dryer either, seal it in a plastic bag for two weeks. That timeframe covers the full life cycle, ensuring any lice or eggs are long dead before the item comes back out. You don’t need to bag everything in the house, just items that had direct contact with the infested person’s head or hair.
What You Don’t Need to Do
You don’t need to fumigate your home, spray furniture with pesticides, or deep-clean carpets. Lice are human parasites, not environmental ones. They cannot survive on pets, and they don’t breed in your couch cushions. Vacuuming the floor and furniture where the infested person sat or lay is reasonable, but the two-day survival window means your effort is better spent on the person’s hair and their immediate bedding than on scrubbing every surface in the house.
You also don’t need to keep your child home from school for days. Both the CDC and the American Academy of Pediatrics recommend that children with lice finish the school day, get treated that evening, and return to class after starting treatment. “No-nit” policies, which require a child to be completely free of eggs before returning, have been discouraged by both organizations. Nits glued to the hair shaft are very unlikely to transfer to another person, and misdiagnosis of nits by non-medical staff is common. The missed school days create a bigger burden on families than the lice themselves.
What About Tea Tree Oil?
Tea tree oil is widely marketed as a lice repellent, but there is no scientific evidence that it prevents infestations. Small studies have shown that tea tree oil combined with lavender oil may help kill some lice and eggs during treatment, but that is different from prevention. Spraying tea tree oil on your child’s hair before school is unlikely to cause harm, but it shouldn’t replace the strategies that actually work: contained hairstyles, regular wet combing checks during outbreaks, and prompt treatment of anyone who is infested.
Preventing Reinfestations
Most “reinfestations” are actually the original case that wasn’t fully treated. Lice eggs hatch on a roughly 7-to-10-day cycle, so a single treatment session often misses newly hatched lice. Follow whatever treatment protocol you’re using with a second session about 9 days later to catch any lice that hatched after the first round.
During those two weeks, continue wet combing every few days to monitor progress. Make sure all household members have been checked and, if needed, treated at the same time. Treating one child while an untreated sibling sleeps in the next bed is the most common reason lice keep coming back. Coordinate with close contacts too. If your child’s best friend also has lice, both families treating simultaneously prevents the cycle from restarting at the next playdate.