The safe, quick way to clear head lice is to confirm a live louse first, treat every person who has an active infestation at the same time, and keep checking and combing for two to three weeks afterward. The CDC’s head lice overview says finding a live nymph or adult louse on the scalp or hair is the best way to diagnose an infestation, and that misdiagnosis is common. Lice crawl and cannot hop or fly, so the work is on heads, not on your house.
Telling a Nit From Dandruff Before Anyone Is Treated
Judge the speck by whether it is stuck. The AAP’s guide for parents says nits are firmly attached to hair while dandruff, dirt or other particles are not, and that nits look like small white or yellow-brown specks near the scalp. The CDC says that if you do not see crawling lice, look for nits attached firmly within 1/4 inch of the base of the hair shafts, and that nits attached farther out than that are almost always hatched or dead. Adult lice run roughly 2 to 3 mm long, about the size of a sesame seed, and a nymph is about the size of a pinhead. Start at the hairline at the back of the neck and behind the ears, where the AAP says they are easiest to find, using this four-step check:
- Seat your child in a brightly lit room and part their hair.
- Wet the hair, then comb small sections with a fine-tooth louse or nit comb.
- Wipe the comb on a wet paper towel after each pass, then examine the scalp, comb and towel.
- Repeat until you have combed through all of the hair.
Hair color can hide all of this. The AAP says some nits blend in with a person’s hair color and get mistaken for dandruff or hair spray droplets. Our post on checking for lice in blonde hair walks through that problem. A magnifying lens helps, and the CDC says that if you are not sure whether someone has head lice, see your healthcare provider instead of reaching for medicine.
Why One Treatment Does Not Always End It
One treatment can fall short because a medicine that kills crawling lice does not always kill the eggs. The CDC’s treatment guidance says some medicines kill lice and eggs, so retreatment is usually not required with those, while others kill lice but not eggs and call for a second treatment about a week later, 7 to 9 days depending on the drug. That decision belongs to the label and to your child’s doctor. The AAP says to check with the doctor before beginning any head lice treatment, to follow the package directions exactly as written, and that medicine should be applied by an adult and never by the child. The eggs set the clock:
| Stage | What the CDC says | What the AAP says |
|---|---|---|
| Nit to hatching | About a week, 6 to 9 days | 7 to 12 days, depending on the surrounding temperature |
| Nymph to adult | About seven days | About 9 to 12 days after hatching |
| Eggs laid per day | About six | Up to 10 a day |
| Adult louse on a head | About 30 days | About 28 days |
That cycle is why the next few weeks matter. The CDC and the AAP both say to check the hair and comb out nits and lice every 2 to 3 days for 2 to 3 weeks after each treatment, and the AAP says the cycle can repeat every 3 weeks if head lice are left untreated. If a few lice are still moving slowly 8 to 12 hours after treatment, the CDC says you do not need to reapply; if you find no dead lice at all, or they look as active as before, it says the medicine may not be working and to talk with a provider before re-treating. The AAP also says head lice can be resistant to the active ingredients in over-the-counter treatments in some communities, and that the likelihood of resistance varies across the country. Our post on treating nits and their eggs stays with that stage.
Home Remedies the CDC and the AAP Tell Families to Skip
Skip the kitchen and garage remedies. The CDC says it does not have scientific evidence that suffocating head lice with mayonnaise, olive oil, margarine, butter or similar substances is an effective form of treatment. The AAP is blunter: do not use petroleum jelly, mayonnaise, tub margarine, essential oils or olive oil, because no studies prove they work, and never use dangerous products like gasoline or kerosene, or medicines made for use on animals. MedlinePlus calls kerosene and gasoline dangerous and flammable. The AAP also says not to spray pesticides in your home, and the CDC says fumigant sprays and fogs are not necessary to control head lice and can be toxic if inhaled or absorbed through the skin. Never place a plastic bag on a child’s head, the AAP adds, calling it dangerous to put anything made of plastic there.
Combing has limits of its own. The AAP says the comb-out method can be used to help check for nits and head lice, but usually does not work on its own to get rid of them, and it calls head lice medicine the most effective way to treat head lice.
Who in the House Gets Checked, and Who Gets Treated
Check everyone in the household, then treat the people who actually have lice. The CDC says to check all household members and other close contacts, and to treat everyone who is infested, plus anyone they share a bed with, at the same time. It also says to treat head lice when there is an active infestation. The AAP states the limit from the other side: medicine should be used only when it is certain that your child has living head lice. Our post on whether the whole family needs lice treatment covers that distinction.
Checking is not a one-day job. The CDC says people with head lice may have no symptoms, particularly with a first infestation or a light one, and that it may take four to six weeks for itching to appear the first time. The AAP says regular checks are a good way to spot head lice before they have time to multiply, and before the scalp becomes sensitive to lice saliva and starts to itch. Before treating a young child, the CDC and MedlinePlus both say to talk with your healthcare provider first.
What to Wash at Home, and What to Leave Alone
Wash the few things that touched the head in the two days before treatment, and leave the rest. Head lice do not survive long off a person, the CDC says, and it puts the risk of catching lice from a louse that has fallen onto a rug, carpet or furniture as very small. It also says spending much time and money on housecleaning is not necessary to avoid reinfestation. The short list worth doing:
- Machine wash and dry clothing, towels and bed linens used in the two days before treatment, using the hot water cycle at 130 degrees Fahrenheit and high heat drying.
- Seal what you cannot wash or dry clean in a plastic bag for two weeks; the AAP says you do not need to throw these things away.
- Soak combs and brushes in hot water, at least 130 degrees Fahrenheit, for 5 to 10 minutes.
- Vacuum the floor and furniture, particularly where the person with lice sat or lay.
Prevention lives on heads, not furniture. The CDC says head lice mainly spread by direct contact with the hair of a person who has them, so teach children to avoid hair-to-hair contact during play and not to share combs, brushes, towels, hats, scarves, coats, sports uniforms, hair ribbons or barrettes. MedlinePlus adds headphones, hair ties and helmets to that list. For perspective, the CDC says head lice transmit no disease and are not considered a health hazard.
Frequently Asked Questions
Why is my child still itching after the lice are gone?
Itching can outlast the lice themselves. The AAP says itching caused by head lice can last for weeks, even after the lice are gone. The CDC explains the itch as an allergic reaction to louse bites and names itching as the most common symptom, along with a tickling feeling in the hair, irritability and sleeplessness. MedlinePlus adds trouble sleeping, because head lice are most active in the dark.
Can my child catch lice from one quick hug?
A brief touch is a poor way to pass lice. The AAP says the main way head lice spread is from close, prolonged head-to-head contact, and that there is a very small chance of spread by sharing items such as combs, brushes, hats and sports helmets. Our post asking whether you can catch lice from a quick hug works through the same question.
Can lice spread in a swimming pool?
Unlikely, says the CDC: head lice can survive under water for several hours but are unlikely to spread in a swimming pool, and chlorine levels in pool water do not kill head lice. The CDC does name a less common route worth knowing, which is lying on a bed, couch, pillow, carpet or stuffed animal that has recently been in contact with a person who has lice.
Can our dog or cat give lice to the kids?
No. The CDC says animals do not get or spread head lice. These are parasitic insects that feed on human blood, and the CDC says you find them mostly on the head, though they can also turn up on the eyebrows and eyelashes. MedlinePlus describes the same thing: tiny insects living on the skin covering the top of the head.
Do we have to get every single nit out?
Not necessarily, and it depends on the medicine. The CDC says nits may stay in the hair after treatment, but that successful treatment will kill crawling lice. The AAP says that after the eggs hatch the empty nits stay on the hair shaft, that some prescription products do not call for nit combing, and that removing nits may help decrease embarrassment to your child or teen. The label and the doctor settle it.
Does a messy house or unwashed hair cause lice?
No. The CDC says getting head lice is not related to the cleanliness of you or your environment, and the AAP says lice can attach to the hair of anyone’s head whether that hair is clean or dirty. MedlinePlus says the same of personal hygiene. For scale, the CDC estimates 6 to 12 million infestations each year in the United States among children 3 to 11 years of age.
How Lice Lifters of Mercer County Can Help
If you would rather not run this whole process yourself, our clinic can take it on. We check the whole family in one place, so a light case on a sibling is not missed, and the treatment we use is non-toxic and done in one visit. Same-day appointments are available when the problem needs handling today rather than next weekend. If you are mid-treatment at home and unsure whether it worked, a head check tells you where you actually stand. Our 30 Day Guarantee applies when the whole family is checked. You can read how our professional lice treatment works, and when you are ready, book a head check for everyone who shares a bedroom or a hairbrush.
