Treating head lice starts with confirming a live louse is there, using a head lice medicine exactly as its label directs, and then checking and combing the hair every two to three days for the next two to three weeks. Preventing them comes down to less head-to-head contact and checking everyone in the household when one person has lice. The American Academy of Pediatrics gives the same first move either way: talk to your child’s doctor before you start any treatment. The CDC says the same about treating young children.
Head lice are crawling insects. They cannot jump, hop or fly, and they spread mainly through close, prolonged head-to-head contact. The CDC estimates that 6 to 12 million infestations occur each year in the United States among children 3 to 11 years of age. Getting them has nothing to do with how clean your home or your child’s hair is, and head lice do not transmit any disease.
Make Sure It Is Really Head Lice Before You Treat
Finding a live nymph (a baby louse) or an adult louse on the scalp or in the hair is the best way to diagnose head lice, according to the CDC’s head lice overview. Confirm that before you buy anything, because misdiagnosis of head lice infestation is common, and the AAP says lice medicine should be used only when it is certain that your child has living head lice. If you are not sure what you are looking at, see your healthcare provider.
Adult lice are 2 to 3 mm long, about the size of a sesame seed, and a nymph is about the size of a pinhead. They avoid light and move quickly, so live lice are hard to find. Eggs are easier: lice attach them to hair close to the scalp, and you will often see nits behind the ears and near the back of the neck.
- Seat your child in a brightly lit room and part the hair all the way down to the scalp in very small sections.
- Comb through the hair in small sections with a fine-toothed louse or nit comb; a magnifying lens can help.
- Wipe the comb on a wet paper towel after each pass, then examine the scalp, the comb and the towel.
- Repeat until you have combed through all of the hair.
Nits are oval, about the size of a knot in thread, and usually yellow to white. Dandruff, dirt and hair spray droplets get mistaken for them; nits are firmly attached to the hair by a sticky substance and those particles are not. Position matters too. Viable eggs sit within a quarter inch of the base of the hair shaft, and nits farther out than that are almost always hatched or dead. If you find no crawling lice and only those far-out nits, the infestation is probably old and does not need treatment.
Itching is the most common symptom, and most of it happens behind the ears or at the back of the neck. A child may also describe a tickling feeling in the hair or sleep poorly, since lice are most active in the dark. Do not wait for itching, though: it can take four to six weeks for itching to appear the first time.
What the CDC and the AAP Say About Lice Medicine
The most effective way to treat head lice is with head lice medicine, available over the counter or by prescription. The AAP’s guide for parents says to check with your child’s doctor before beginning any treatment, and the CDC says to consult your healthcare provider before treating young children. These medications are generally safe and effective when used correctly.
The CDC lists these active ingredients for treating head lice. The youngest age on the label and the effect on eggs are what change your plan.
| Active ingredient | How you get it | Youngest age on the label | Effect on lice eggs |
|---|---|---|---|
| Permethrin lotion, 1% | Over the counter | Two months and older | Kills live lice but not unhatched eggs |
| Pyrethrins with piperonyl butoxide | Over the counter | Two years and older | Kills live lice only, not unhatched eggs |
| Benzyl alcohol lotion, 5% | Prescription | Six months and older | Kills lice but does not kill eggs |
| Ivermectin lotion, 0.5% | Prescription | Six months and older | Does not kill eggs, but appears to prevent newly hatched lice from surviving; one application, no nit combing |
| Malathion lotion, 0.5% | Prescription | Six years and older | Kills live lice and some eggs; can irritate skin and is flammable |
| Spinosad 0.9% topical suspension | Prescription | Six months and older | Kills live lice and unhatched eggs, so retreatment is usually not needed |
The label governs the details, and a few rules hold across all of them. Follow the package directions exactly as written. An adult should apply the medicine, children should never apply it, and no child should be left alone with medicine in his or her hair. Do not use a combination shampoo and conditioner, or a conditioner, before the medicine, and do not re-wash the hair for one to two days after it comes out. Rinse over a sink with warm water, not hot. Keep these products out of the eyes and flush immediately if any gets in. Do not use two different lice drugs at the same time unless a doctor or pharmacist tells you to. Some are flammable, so skip smoking, hair dryers, curlers, curling irons and flat irons during treatment.
Sitting still through an application and a comb-out asks a lot of a young child. Our notes on keeping your child calm during head lice treatment cover what helps.
Why One Application Is Rarely the End of It
Expect a second pass, because the medicine you use may kill crawling lice without killing their eggs. According to the CDC’s treatment guidance, when a medication kills lice but not eggs you treat again about a week after the first treatment, 7 to 9 days depending on the drug, after the eggs have hatched but before new eggs are produced. When a medication kills both, retreatment may not be necessary.
That window follows the life cycle. Nits hatch in about a week, a range of 6 to 9 days, and a nymph takes about seven days to mature into an adult. An adult female can lay about six eggs each day, and an adult louse can live on a person’s head for about 30 days. The AAP adds that this cycle can repeat every three weeks if head lice are left untreated.
After each treatment, the CDC says to check the hair and remove nits and lice every two to three days for the next two to three weeks. Nits may stay in the hair after treatment, and empty shells stay attached to the hair shaft after hatching, so a nit you spot is not proof of failure. Treat again only if live, crawling lice are there several days later, and talk to your healthcare provider before re-treating. If a few lice are still moving slowly 8 to 12 hours after treatment, there is no need to reapply; if you find no dead lice, or they seem as active as before, the medicine may not be working.
Combing is a companion to the medicine, not a substitute; the AAP says the comb-out method usually doesn’t work on its own to get rid of head lice. If you want to know how much time to set aside, we break down how long a head lice treatment takes.
When the First Treatment Does Not Work
Call the doctor before you reach for a third product. The CDC lists the reasons treatment fails: misdiagnosis, recent application of a combination shampoo and conditioner or of conditioner, not following the treatment instructions, head lice resisting the medication, and reinfestation after successful treatment. Each one has a different answer, and a pediatrician can tell them apart.
Resistance is real, and it is local. The AAP says head lice can be resistant to the active ingredients in over-the-counter treatments in some communities, that the likelihood varies across the country, and that prescription products may need to be used in the initial treatment in some communities based on local resistance patterns. The CDC notes some resistance to 1% permethrin, with the prevalence unknown. The AAP’s advice is to call your pediatrician before treatment and let them help you choose.
There are limits on repeating. These drugs are insecticides and can be dangerous if misused or overused, so do not treat a person more than two or three times with the same medication when it is not working, and check with your child’s doctor before beginning a second or third medicine. If crawling lice are still present after a full course of treatment and retreatment, the CDC says to consider an alternative medication.
What about oils, mayonnaise and other home remedies?
Evidence does not support them. The CDC says there is no scientific evidence that suffocating head lice with mayonnaise, olive oil, margarine, butter or similar substances is an effective form of treatment, and the AAP says no studies prove that petroleum jelly, tub margarine or essential oils work either. Two cautions outrank the question of effectiveness. Never use gasoline or kerosene, which are flammable and carry substantial risk, or medicines made for use on animals. And never place a plastic bag, or anything made of plastic, on a child’s head.
How to Keep Lice From Spreading Through the Household
Check every head in the house on the same day. The CDC says to check all household members and other close contacts, and to treat everyone with an active infestation, plus anyone they share a bed with, at the same time. Treating one child while a sibling or a parent is carrying lice sets up a second round.
Head-to-head contact is the main route, so the habits worth teaching are the ones that reduce it during play, sports, sleepovers and camp. Teach children not to share what touches their heads: hats, scarves, coats, sports uniforms, hair ribbons, barrettes, headphones, hair ties and helmets, plus combs, brushes and towels. The AAP says there is a very small chance lice spread that way, and regular checks are a good way to spot head lice before they have time to multiply.
The cleaning list is short. Head lice die within two days if they fall off a person and cannot feed, and the CDC says the risk of catching lice from one that has fallen onto a rug, carpet or furniture is very small, so spending much time and money on housecleaning is not necessary. These steps cover it:
- Machine wash and dry anything the person wore or used in the two days before treatment, using hot water at 130 degrees Fahrenheit and high heat drying.
- Seal what you cannot wash or dry clean in a plastic bag for two weeks; you do not need to throw it away.
- Soak combs and brushes in hot water, at least 130 degrees Fahrenheit, for 5 to 10 minutes.
- Vacuum the floor and furniture where the infested person sat or lay.
- Skip fumigant sprays and fogs. They are not necessary to control head lice and can be toxic if inhaled or absorbed through the skin.
Frequently Asked Questions
What is the best treatment for head lice?
The best one is the head lice medicine your child’s doctor picks with you, since the right choice depends on your child’s age, what you have already tried, and resistance patterns where you live. Over-the-counter treatments sometimes are not the most effective, and several prescription options are approved from six months of age.
How do you treat nits?
Nits come off mechanically, with a fine-toothed nit comb worked through small sections of hair. They are glued on with a sticky substance, which is why they resist brushing and rinsing. With spinosad topical suspension, nit removal is not required at all. Removing nits may help decrease embarrassment for a child or teen.
Why is my child still itching after the lice are gone?
Itching is an allergic reaction to louse bites, and the AAP says it can last for weeks after the lice are gone. Some lice medications cause itching or a mild burning sensation of their own. Sores from scratching can become infected, so ask your child’s doctor about any that look worse rather than better.
Can head lice spread in a swimming pool?
It is unlikely. Head lice can survive under water for several hours, and chlorine levels in pool water do not kill them, but the CDC says lice are unlikely to spread in a swimming pool. Sharing a towel, comb or hair tie afterward is the route worth avoiding.
Can pets give our family head lice?
No. Animals do not get or spread head lice, which are human parasites that feed on human blood and live on the scalp, with occasional stops on the eyebrows and eyelashes. A dog or cat in the house changes nothing about how you check or treat your family.
Where can I find lice treatment near me?
Our clinic finder is the fastest route: use it to find a Lice Lifters clinic near you, then contact that location directly. If you want to compare options first, our guide to choosing a lice treatment center near you covers the questions worth asking before you book.
When You Want Help From a Lice Lifters Clinic
Some families would rather hand this off than run two weeks of comb-outs. That is what our clinics do: certified technicians check each family member, work through the hair with a nit comb, and apply our non-toxic, enzyme-based solution, which is safe for all ages and carries 99.9% efficacy. Same-day appointments are available, and our 30 Day Guarantee applies when the whole family is checked. You can read what to expect at a professional lice treatment clinic, then find a Lice Lifters clinic near you. Whatever you decide, keep up the follow-up checks at home, and call your child’s doctor with anything medical.
