Head lice are tiny wingless insects, 2 to 3 mm long (about the size of a sesame seed), that live on the human scalp and feed on blood. They do not carry or transmit disease. The CDC estimates 6 to 12 million infestations each year in the United States among children ages 3 to 11, which makes lice one of the most common conditions of elementary school. Getting lice is not a sign of poor hygiene or a dirty home. Lice are equally happy on clean hair.

Head lice spread almost entirely through direct head-to-head contact, which is why they move fastest during sleepovers, sports, selfies, and playground huddles. Sharing hats, brushes, helmets, or pillows can spread them, but that is far less common. Lice die within about two days off a scalp, so couches, carpets, and car seats are a very low risk. Lice do not come from pets, dirty houses, or poor hygiene.

The most common sign is itching that starts behind the ears and at the nape of the neck, along with a tickling feeling of something moving in the hair. You may also see live lice, nits glued to hair shafts, small red bumps on the scalp or neck, and restless sleep, because lice are most active in the dark. On a first infestation, itching can take 4 to 6 weeks to begin, so a child can have lice well before scratching starts. Check under bright light or in daylight, section by section.

Adult lice are 2 to 3 mm long, roughly a sesame seed, tan to grayish white, and they move fast away from light. Nits are much smaller, about 0.8 mm, oval, and cemented to the side of a single hair shaft. The reliable test is whether it moves: dandruff and hair product flakes slide off or brush away, and nits do not budge without a comb or your fingernails. Nits within a quarter inch of the scalp are usually live. Nits further down the shaft are almost always already hatched or dead.

No. Head lice cannot jump, hop, or fly. They have no wings and no jumping legs, so crawling is the only way they move, which is why head-to-head contact accounts for nearly every case. Fleas jump, and that is usually where the confusion starts. A louse that falls onto a couch or a car seat cannot leap back onto anyone, and it will die within about two days because it cannot feed.

Nit Happens cleared lice in 95.8% of cases in a clinical study when families completed the full protocol, and 89% across all participants including re-infestations (H.A.L.T. trial, n=26, IRB approved). It works physically rather than chemically, using food-grade diatomaceous earth and plant oils, with no pesticides, no prescription, and no neurotoxins. The full treatment runs about 45 minutes. Apply the treatment gel to dry hair, work it in for 15 to 20 minutes, wait 10 minutes, follow with the removal shampoo, then comb through with the enclosed lice comb. Repeat the full treatment in 7 days to catch anything that hatched after round one. A dermatologist-controlled patch study reported zero adverse events, so it is suitable for sensitive skin.

Wash bedding, towels, hats, and clothing used in the two days before treatment in hot water at 130°F or higher, then dry on high heat. Soak combs and brushes in 130°F water for 5 to 10 minutes. Seal anything you cannot wash, like stuffed animals, in a plastic bag for two weeks. Vacuum the floors and furniture where the person sat or slept. Skip the lice fogger sprays entirely. The CDC advises against them because they can be toxic to inhale and they are unnecessary, since lice die within about two days off a scalp. You do not need to deep clean the whole house.

No. Dogs, cats, and other pets cannot catch head lice, carry them, or pass them between people. Human head lice (Pediculus humanus capitis) feed only on human blood and die within about two days off a human scalp. The lice that affect animals are entirely different species and cannot live on humans. There is no reason to treat, bathe, or shave a pet during a lice outbreak.

An adult head louse lives about 30 days on a scalp and dies within about two days once it falls off, because it cannot survive without feeding. A female lays about 6 eggs a day. Nits hatch in 6 to 9 days and take roughly another 7 to 10 days to reach adulthood and start laying. That life cycle is exactly why a second treatment 7 days after the first matters. It catches the nits that hatched after round one, before they are old enough to lay eggs of their own.

Three things cause nearly every repeat case: nits were missed during combing, the second treatment 7 days later was skipped, or the child was re-exposed by a friend or family member who was never checked. Resistance is the fourth. Lice across the United States now widely carry mutations that make traditional permethrin and pyrethrin products less effective, which is the origin of the term super lice. Nit Happens works by physical action rather than a neurotoxin, so resistance does not apply to it. Keep combing every 2 to 3 days for two weeks after treatment.

No, in most cases. The American Academy of Pediatrics recommends that children not be sent home early or excluded from school because of head lice, since classroom transmission is low, and it advises schools to abandon no-nit policies. Start treatment the same day and let the school nurse know. Individual districts still set their own rules, so it is worth checking yours, but the national pediatric guidance is that a child with lice can stay in class.

Treat only the people who actually have live lice, but check every household member the same day, focusing behind the ears and at the nape of the neck. Treating people who are not infested wastes product and prevents nothing. The one exception worth considering is anyone who shares a bed with the infested person, since hours of head-to-head contact make them the most likely next case. Recheck everyone in a week when you do the second treatment.

Yes. Nit Happens is HSA and FSA eligible. Enter your benefits card at checkout exactly like a credit card, with no prescription or letter of medical necessity needed, because lice treatment qualifies as an eligible medical expense. If your card is declined because your plan administrator flags the merchant category, pay with a regular card and submit the emailed receipt to your administrator for reimbursement.