Head Lice Aren't About Cleanliness, Mostly Head-to-Head
The Centers for Disease Control and Prevention (CDC) says getting head lice is not related to cleanliness of you or your environment; the most common way to get them is head-to-head contact with a person who already has head lice, and this contact can be common among children playing at places like school or the home. CDC also says head lice do not transmit any disease and therefore are not considered a health hazard; both over-the-counter and prescription medications treat head lice.
CDC says that in the United States, head lice infestation is most common among preschool- and elementary school-age children and their household members and caretakers; CDC's reminder is that you do not need to send students with head lice home early from school: they can go home at the end of the day, be treated, and return to class after beginning appropriate treatment. This article follows CDC's head lice overview page on symptoms, how lice spread, how to prevent them, and how to confirm head lice. Everyone's health is different; if you have questions, ask your healthcare provider.
What head lice are and their symptoms
CDC explains (CDC head lice overview):
- What they are: parasitic insects that feed on human blood, found mostly on the head but also on eyebrows and eyelashes; adults are roughly 2–3 mm long, about the size of a sesame seed.
- Symptoms: itching is the most common symptom and is an allergic reaction to louse bites; the first time a person has head lice, itching may take four to six weeks to appear.
- Other symptoms: a tickling feeling or a sensation of something moving in the hair; irritability and sleeplessness; sores from scratching, which can sometimes become infected with bacteria normally found on the skin.
- Maybe no symptoms: people may have no symptoms, particularly with a first infestation or when it is light.
How they spread
- Head to head: mainly by direct contact with the hair of a person who has lice; lice crawl and cannot hop or fly.
- Less common ways: wearing hats, scarves, coats, sports uniforms, or hair ribbons worn by a person with lice; using their combs, brushes, or towels; lying on a bed, couch, pillow, carpet, or stuffed animal recently in contact with them.
- Off the scalp: adult lice live about 30 days on a person's head but die within two days if they fall off and cannot feed; nits usually die within a week if not kept at the temperature found close to the scalp.
- Pools and animals: lice can survive under water for several hours but are unlikely to spread in a swimming pool, and pool chlorine does not kill them; animals do not get or spread head lice.
How to prevent them
- Avoid head-to-head contact: avoid head-to-head (hair-to-hair) contact during play and other activities at home, school, and elsewhere (sports, playground, slumber parties, camp).
- Don't share clothing: do not share hats, scarves, coats, sports uniforms, hair ribbons, or barrettes.
- Don't share combs or towels: do not share combs, brushes, or towels; soak combs and brushes used by a person with lice in hot water (at least 130°F) for 5–10 minutes.
- Don't lie down: do not lie on beds, couches, pillows, carpets, or stuffed animals recently in contact with a person with head lice.
- Wash and dry: machine wash clothing, towels, bed linens, and other items the person wore or used during the two days before treatment in hot water (130°F) and dry on high heat; if items can't be washed or dry cleaned, seal them in a plastic bag for two weeks.
- Vacuum: vacuum the floor and furniture, especially where the person sat or lay; CDC says spending much time and money on housecleaning is not necessary.
- No fumigant sprays: do not use fumigant sprays or fogs; they are not necessary to control head lice and can be toxic if inhaled or absorbed through the skin.
- Teach children: during an outbreak in a community, school, or camp, teach children to avoid hair-to-hair contact during play and not to share hats, hair ribbons, barrettes, scarves, coats, or sports uniforms, or combs, brushes, or towels.
How to confirm
- Often misdiagnosed: CDC says misdiagnosis of head lice is common; finding a live nymph or adult louse on the scalp or hair is the best way to diagnose it.
- Hard to find: adults and nymphs are very small, move quickly, and avoid light, so they may be hard to find; a fine-toothed louse comb may help.
- Look for nits: if you don't see crawling lice, look for nits attached firmly within ¼ inch of the base of hair shafts, often behind the ears and near the back of the neck; nits more than ¼ inch from the base are almost always hatched or dead.
- Don't confuse them: nits are often confused with dandruff, hair spray droplets, and dirt particles; a magnifying lens may help.
- Old infestation: if you see no nymphs or adults and the only nits are more than ¼ inch from the scalp, the infestation is probably old and does not need treatment.
- If unsure: if you are not sure whether a person has head lice, see your healthcare provider.
For asking a pharmacist how to choose over-the-counter medicine, see Ask the Pharmacist First, on Choosing and Using OTC Medicine; for where to go when you’re sick, see ERs Can't Refuse the Uninsured, Ask for Self-Pay Estimates.
What this article didn't cover
- Treatment: CDC has a separate treatment page; which medicines to use and how was not covered here.
- School rules: CDC's reminder is that early dismissal isn't needed; individual schools' own rules were not checked.
- Page date: this page is from June 2024; it was reopened on the day of writing and had not changed.
FAQ
Do children get head lice because they aren't clean?
No. CDC says getting head lice is not related to cleanliness of you or your environment.
Should I pick my child up from school right away if lice are found?
CDC says you do not need to send students with head lice home early; they can go home at the end of the day, be treated, and return to class after beginning appropriate treatment.
Do I need to deep-clean the house or spray insecticide?
No. CDC says spending much time and money on housecleaning is not necessary, and fumigant sprays or fogs should not be used: they are not necessary and can be toxic.
Can head lice spread to our cats or dogs?
No. CDC says animals do not get or spread head lice.
Sources and dates checked
All checked on 2026-11-03.
- CDC, About Head Lice (page dated 2024-06-04):https://www.cdc.gov/lice/about/head-lice.html