Head Lice


Head lice are tiny wingless insects. They live among human hairs and feed on blood from the scalp.

Head lice are a common problem, especially for kids. They spread easily from person to person, and sometimes are tough to get rid of. Their bites can make a child's scalp itchy and irritated, and scratching can lead to infection.

Head lice are annoying, but they're not dangerous and they don't spread disease. They're not a sign of poor hygiene — head lice need blood and they don't care whether it's from someone who's clean or dirty.

It's best to treat head lice right away to prevent them from spreading.

What Are the Signs & Symptoms of Head Lice?

Even though they're tiny, you can see head lice. Here's what to look for:

  • Lice eggs (nits). These look tiny yellow, tan, or brown dots before they hatch. Lice lay nits on hair shafts close to the scalp, where the temperature is perfect for keeping warm until they hatch. Nits look a bit dandruff, but aren't removed by brushing or shaking them off.Unless a child has many head lice, it's more common to see nits in the hair than live lice crawling on the scalp. Lice eggs hatch 1–2 weeks after they're laid. After hatching, the remaining shell looks white or clear and stays attached to the hair shaft. This is when it's easiest to spot them, as the hair is growing longer and the egg shell is moving away from the scalp.
  • Adult lice and nymphs (baby lice). Adult lice are no bigger than a sesame seed and are grayish-white or tan. Nymphs are smaller and become adult lice about 1–2 weeks after they hatch. This life cycle repeats itself about every 3 weeks. Most lice feed on blood several times a day, and they can survive up to 2 days off the scalp.
  • Scratching. With lice bites come itching and scratching. This is due to a reaction to the saliva (spit) of lice. But the itching doesn't always start right away. It depends on how sensitive a child's skin is to the lice. It might take weeks for kids with lice to start scratching. They may complain, though, of things tickling or moving around on their heads.
  • Small red bumps or sores from scratching. Some kids have mild irritation from scratching, while others may get a bothersome rash. Scratching a lot can lead to a bacterial infection. Watch for swollen lymph nodes (glands) on the back or front of the neck, and red, tender skin that might have crusting and oozing. Doctors can treat a skin infection with an antibiotic.

How Can I Check My Child for Head Lice?

Look for lice and nits on the scalp, behind the ears, and around the nape of the neck. It's rare for lice to be in eyelashes or eyebrows.

It can be tough to find a nymph or adult louse. Usually, there aren't many of them and they move fast. Look for nits attached to the hair near the scalp. They can look dandruff or dirt. To tell them apart, pull on the little speck with your fingers — dandruff and dirt can be removed, but nits stay stuck. A magnifying glass and a bright light can help with your inspection.

The best way to check is by using a fine-tooth comb on wet hair. After applying lots of conditioner, comb the hair out in very small sections, and look for lice or nits on the comb. You can wipe the comb onto a tissue or paper towel where it will be easier to see them. 

If your child is itchy and scratching their head but you're not sure if it's lice, ask your child's doctor or the nurse at school or childcare center to take a look.

How Are Head Lice Treated?

The two main ways to treat lice are:

  • medicine
  • removing by hand

Medicine: Medicated shampoos, cream rinses, and lotions are available that kill lice. These may be over-the-counter (OTC) or prescription medicines. If you buy OTC, be sure it's safe for your child's age. While some over-the-counter shampoos are safe for kids as young as 2 months, others are safe only for kids 2 years and older.

In some areas, lice have developed resistance to some medicines. This means they no longer work to kill the lice. Ask your doctor or a pharmacist to recommend a medicine known to work in your area. The doctor also can prescribe a medicated shampoo or lotion. For very resistant lice, the doctor might recommend taking medicine by mouth.

Whether the medicine is OTC or prescription, always follow the directions closely. Applying too much can be harmful. Applying too little won't work.

Removing by hand: Removing lice and nits by hand can finish the job if the medicine did not completely rid your child of lice (no medicine is 100% effective). It is also an option for anyone who doesn't want to use an insecticide. And it is the only option for children 2 months old or younger, who should not use medicated lice treatment. 

To do this, use a fine-tooth comb on wet, conditioned hair every 3–4 days for 3 weeks after the last live louse was seen. Wetting the hair temporarily stops the lice from moving, and the conditioner makes it easier to get a comb through the hair.

There's no need to buy electronic combs that claim to kill lice or make nits easier to remove. No studies have been done to back up these claims. You also don't need to buy special vinegar solutions to apply to the scalp before picking nits. Water and conditioner works fine.

Though petroleum jelly, mayonnaise, or olive oil are sometimes used to try to suffocate head lice, these treatments may not work. If medicine doesn't work and you want to try these methods, talk to your doctor first.

A few important things to NOT do: Don't use a hairdryer after applying scalp treatments. Some treatments for lice use flammable ingredients and can catch on fire. Don't use pesticide sprays or hire a pest control company to try to get rid of the lice; these can be harmful.

Don't use essential oils (such as ylang ylang oil or tea tree oil) to treat lice on the scalp. They can cause allergic skin reactions and aren't approved by the U.S. Food and Drug Administration (FDA).

 Don't ever use highly flammable chemicals such as gasoline or kerosene on anyone.

Are Head Lice Contagious?

Head lice spread quickly from person to person, especially in group settings schools, childcare centers, slumber parties, sports activities, and camps.

They can't fly or jump, but they have claws that let them crawl and cling to hair. They spread through head-to-head contact, and sharing clothing, bed linens, combs, brushes, and hats.

Pets can't catch head lice and pass them on to people or the other way around.

Do Kids Have to Stay Home From School?

In the past, kids with head lice were kept home from school. But now doctors don't recommend these “no-nit” policies.

In most cases, a child who has lice should stay at school until the end of the day, go home and get treatment, and return to school the next day.

While they are at school, kids should avoid head-to-head contact with other kids. It can help to put long hair up in a bun, braid, or ponytail.

Can We Prevent Head Lice?

To get rid of head lice and their eggs, and to help prevent them from coming back:

  • Wash all bed linens, stuffed animals, and clothing used during the 2 days before treatment (any lice that fell off before that will not be alive). Wash in very hot water (130°F [54.4°C]), then put them in the hot cycle of the dryer for at least 20 minutes.
  • Dry clean items that can't be washed. Or put them in airtight bags for 2 weeks.
  • Vacuum carpets and any upholstered furniture (in your home or car), and throw away the vacuum cleaner bag.
  • Soak hair-care items combs, barrettes, hair ties or bands, headbands, and brushes in hot water or throw them away. Tell kids not to share these items.
  • Because lice easily pass from person to person in the same house, check all family members. Treat everyone who has lice so they won't pass it back and forth.
  • Tell kids to try to avoid head-to-head contact at school (in gym, on the playground, or during sports) and while playing at home with other children.
  • Every 3 or 4 days, check kids who had close contact with a person who has lice. Then, treat any who have lice or nits close to the scalp.

Will They Ever Be Gone?

As many parents know, fighting head lice can be an ongoing battle. There's no doubt that they can be hard bugs to get rid of.

If you've tried everything and your child still has lice, it could be because:

  • some nits were left behind (if you see nits far from the scalp — more than ½ inch (1 cm) — and no live lice, these are probably dead and treatment ly isn't needed)
  • your child is still around someone who has lice
  • the treatment you're using isn't effective

If your child has lice 2 weeks after you started treatment or if your child's scalp looks infected, call your doctor.

There are professional lice treatment centers that remove lice and nits for a fee. These services are effective but often costly.

Looking Ahead

Remind your child that while having lice can be embarrassing, anyone can get them. Having head lice is not a sign of dirtiness or poor hygiene. The pesky little bugs can be a problem no matter how often kids do — or don't — wash their hair or bathe.

Dealing with head lice can be frustrating, but be patient. Follow the treatments and prevention tips from your doctor, and soon your family will be lice-free.

Reviewed by: Michelle P. Tellado, MD

Date reviewed: September 2019

Source: https://kidshealth.org/en/parents/head-lice.html

VIDEO: Head Lice Up Close, And All Too Personal


At the end of spring break, your kids might be bringing back something more than just good memories of that family vacation. Holidays, it turns out, are a time when head lice spread.

Any time kids' noggins are in direct contact with each other, or when parents and children spend time cuddling, lice have a chance to crawl from one head to the next.

Melissa Shilliday, who owns two NitPixies hair salons in Northern California, says she often sees an uptick in her lice-combing business after holidays or when popular movies for children come out in theaters.

At the salons, for $115 per person, a technician will comb lice the client's hair with a special metal comb that has closely spaced, narrow teeth and then follow that up with a treatment of certain oils from plants.

“It's always slow a couple of weeks before a Pixar movie comes out,” Shilliday notes.

Head lice on humanscan move only by crawling on hair. They glue their eggs to individual strands, close to the scalp, where the heat helps them hatch. They tend to feed on blood several times a day.

And although head lice can spread by laying their eggs in sports helmets and baseball caps, the main way they get around is by crawling from one head to another — using relatively large, scythe-shaped claws.

A head louse hides among blond human hairs. The insect's grip is firm, thanks to large tarsal claws that enable it to scamper quickly from one hair to the next.

Josh Cassidy/KQED

Each claw works in unison with a small and spiky, thumb part called a spine. With a claw and spine at the end of each of its six legs, a louse is able totightly grasp a hair strand, or quickly crawl from hair to hair a speedy acrobat.

The insect's drive to stay on a human head is strong; once it's off the scalp and loses access to a blood meal, it will starve and die within 15 to 24 hours.

Lice that live on other primates and birds are all very different looking and have adapted to their unique circumstances, surviving in their host's hair or feathers.

For example, lice that live in pigeon feathers are long and thin, the better to hide in the feathers' barbs, where preening birds can't get to them.

On humans and other primates, lice claws have evolved to fit neatly around a single strand of hair.

“The curvature of it is probably pretty close to the average hair diameter that they would come in contact with for a given species of host,” says biologist David Reed, who has studied lice and evolution at the Florida Museum of Natural History.

The good news is that human head lice can't really move to other parts of our body or onto our pets. They're confined to the head.

At the end of each of its six legs, a head louse has a tarsal claw and a spine, giving it a grip that neatly fits the diameter of a human hair.

Josh Cassidy/KQED

“The claw and spine are adapted to hold [onto] a human hair on the scalp,” says medical entomologist Kosta Mumcuoglu, who studies lice at the Hebrew University of Jerusalem. “The other hairs of the body are usually too thick for them,” he says, “and they can't hold them.”

However, two other types of lice can live elsewhere on the human body: the clothing louse, which lives in the clothes of people who can't change them often enough, and the pubic louse, which spreads during sexual contact.

“[The pubic louse] has stronger claws,” Mumcuoglu notes, “to catch the thicker hairs of that region.”

Between 2013 and 2015, John Clark and colleagues at the University of Massachusetts Amherst tested head lice in every state except West Virginia and Alaska. They found that the insects had become overwhelmingly resistant to the chemicals used in the most common over-the-counter lice treatments: natural insecticides called pyrethrins and the analogous synthetic versions, pyrethroids.

The egg of a head louse is attached to a single hair strand with a glue made hard protein.

Josh Cassidy/KQED

However, other products do still work against lice, Clark says. Prescription treatments that contain the insecticides ivermectin and spinosad are effective louse killers — they're useful against louse eggs, as well as the adult insects.

And treatments that work as suffocants — blocking the lice's breathing holes — and hot-air devices that desiccate the lice also work. Tea tree oil can work both as a repellent and a “pretty good” insecticide, Clark adds.

And then there's combing, which can be surprisingly effective.

“It takes time and effort,” he says. “You sort of have to know what you're doing. And so most people that comb eventually get tired of it and they want something a little bit more simplistic.”

Carefully combing every inch of hair from scalp to tip to remove lice eggs as well as adult insects is, indeed, a laborious, old-fashioned process that has become the last resort for many parents, as lice have become resistant to over-the-counter insecticide shampoos.

NitPixies advises the parents of its clients to continue to use the metal comb on their kids daily for at least five days after treatment to remove any remaining eggs. It generally takes eggs six to nine days to hatch.

This post and video were produced by our friends at Deep Look, a wildlife video series from KQED and PBS Digital Studios that explores “the unseen at the very edge of our visible world.” KQED's Gabriela Quirósis the coordinating producer of the series.

“,”author”:”Gabriela Quirós”,”date_published”:”2019-03-26T13:10:00.000Z”,”lead_image_url”:”https://media.npr.org/assets/img/2019/03/25/dl_606headlice_adult_female_louse_on_human_hairs_blood_meal_visible1_wide-a822c47423f3bec3a8be1ea0b475fc36831352c0.jpg?s=1400″,”dek”:null,”next_page_url”:null,”url”:”https://www.npr.org/sections/health-shots/2019/03/26/706616008/video-head-lice-up-close-and-all-too-personal”,”domain”:”www.npr.org”,”excerpt”:”Claws of the louse that afflicts human scalps fit neatly around a single human hair. Louse eggs stick to hair shafts with a sort of glue. Maybe the best remedy for you and the kids? Comb, baby, comb.”,”word_count”:942,”direction”:”ltr”,”total_pages”:1,”rendered_pages”:1}

Source: https://www.npr.org/sections/health-shots/2019/03/26/706616008/video-head-lice-up-close-and-all-too-personal

Head Lice Fact Sheet


The head louse is an insect that can infest people. These tiny insects (about 1/8” long) make their home in human hair and feed on blood. Head lice multiply rapidly, laying small greyish-colored, oval-shaped eggs (called nits) which they glue to the base of the hair, close to the scalp. Head lice are not known to spread disease.

Who can get head lice?

Anyone can get head lice. They are not a sign of being dirty. Most people don’t know they are infested until they see the nits or lice. They are found throughout the world, most commonly on children.

How does a head lice infestation occur?

Head lice have no wings and do not fly or jump, but they can crawl or run through hair quickly. Most commonly, head lice are spread by direct head-to-head contact with an infested person. They may also be spread by sharing personal items such as combs, brushes, other hair-care items, towels, pillows, hats, and other head coverings. Dogs, cats, and other pets do not spread head lice.

What are the signs of a head lice infestation?

Look closely for nits along the hairline at the back of the head and neck and behind the ears. Nits should not be confused with an accumulation of hair spray, hair gels, or dandruff, which can be easily flicked off the hair; nits cannot because they are firmly attached to individual hairs.

One telltale sign of head lice is a persistent itching of the scalp, which is sometimes accompanied by infected scratch marks or what appears to be a rash.

If you have questions about the diagnosis of head lice, call your doctor.

How do you treat head lice?

The recommended treatment includes using either an over-the-counter (OTC) or prescription medicated (lice-killing) product. Effective head lice treatments include products such as:

  • “Nix,” a cream rinse product available OTC which contains permethrin, a synthetic insecticide
  • Many brands of pyrethrin-based shampoo products (“Rid,” “R&C,” “Triple-X,” etc.) which are also available OTC
  • “Ovide,” a prescription drug containing malathion.

With all of these products, the lice are often killed with one treatment; however, a second treatment seven to 10 days later is often necessary to ensure all of the nits are killed.

Because of increasing numbers of reports of treatment failure with the OTC products, make sure to carefully follow all the instructions on the product label and talk to your health care provider if lice persist.

Additional prescription alternatives are available.

What are some examples of alternative treatments?

Many alternatives to OTC or prescription head lice control products have been suggested.

Although there is little scientific information to support these methods, successful treatment has been reported using several alternative treatments when conventional treatments haven’t worked, or when there is a concern about the toxicity of using head lice control products repeatedly.

The Minnesota Department of Health cannot recommend these treatments without further evidence of their effectiveness. However, we feel it is important to mention some of the more commonly used methods.

The alternative treatments listed below are referred to as suffocants. When applied, the treatment may suffocate and/or create a habitat unfavorable to the head lice.

  • Petroleum jelly (Vaseline®)
  • Mayonnaise
  • Oil (e.g. vegetable, olive, or mineral)

Manual removal of lice and nits by parents or professional services may be an effective supplement or alternative to OTC and prescription treatments.

How should you clean up the environment?

Head lice cannot survive off the human body for more than two days. They do not reproduce off the body. They do not live on pets. Any nits that fall off the head will not hatch or reattach. While most head lice control should focus on treating infested people, some simple things can be done in the environment:

  • Wash bedding in hot water (above 130° F) and dry in a hot dryer. Wash and dry recently worn clothing (including coats, caps, and scarves) in hot temperatures.
  • Clean combs, brushes and similar items by heating in water of at least 130° F for 10 minutes.
  • Clean floors, carpeting, and furniture by thorough vacuuming only. The use of insecticide sprays is not recommended.

Cleaning efforts should happen on the day of the first lice treatment and whenever live lice are found on the patient’s head. Focus on cleaning areas and items the infested person had contact with 48 hours before treatment.

How do you prevent a head lice infestation?

Parents are encouraged to check their children’s heads for lice on a regular basis throughout the year. Families should not depend on someone else to check a child’s head – this may delay treatment.

Remember, if one person in a family, camp, or school has head lice, there’s a chance others will too. Check everyone, and use the same treatment if necessary.

Treating people without lice or nits is not recommended.

How should schools control head lice?

Schools should encourage parents to check their children regularly for lice at home. Wide-spread head lice screening efforts by schools have not been shown to be effective.

When a case of head lice is suspected, parents should be advised at the end of the day to check their children for lice and treat them if an infestation is found. Children with head lice infestations can go to school.

Source: https://www.health.state.mn.us/diseases/headlice/headlice.html

Head lice | Pediculosis

URL of this page: https://medlineplus.gov/headlice.html

Head lice are tiny insects that live on people's heads. Adult lice are about the size of sesame seeds. The eggs, called nits, are even smaller – about the size of a dandruff flake. Lice and nits are found on or near the scalp, most often at the neckline and behind the ears.

Head lice are parasites, and they need to feed on human blood to survive. They are one of the three types of lice that live on humans. The other two types are body lice and pubic lice. Each type of lice is different, and getting one type does not mean that you will get another type.

How do head lice spread?

Lice move by crawling, because they cannot hop or fly. They spread by close person-to-person contact. Rarely, they can spread through sharing personal belongings such as hats or hairbrushes. Personal hygiene and cleanliness have nothing to do with getting head lice. You also cannot get pubic lice from animals. Head lice do not spread disease.

Who is at risk for head lice?

Children ages 3-11 and their families get head lice most often. This is because young children often have head-to-head contact while playing together.

What are the symptoms of head lice?

The symptoms of head lice include

  • Tickling feeling in the hair
  • Frequent itching, which is caused by an allergic reaction to the bites
  • Sores from scratching. Sometimes the sores can become infected with bacteria.
  • Trouble sleeping, because head lice are most active in the dark

How do you know if you have head lice?

A diagnosis of head lice usually comes from seeing a louse or nit. Because they are very small and move quickly, you may need to use a magnifying lens and a fine-toothed comb to find lice or nits.

What are the treatments for head lice?

Treatments for head lice include both over-the-counter and prescription shampoos, creams, and lotions.

If you want to use an over-the-counter treatment and you aren't sure which one to use or how to use one, ask your health care provider or pharmacist.

You should also check with your health care provider first if you are pregnant or nursing, or if you want to use a treatment on a young child.

Follow these steps when using a head lice treatment:

  • Apply the product according to the instructions. Only apply it to the scalp and the hair attached to the scalp. You should not use it on other body hair.
  • Use only one product at a time, unless your health care provider tells you to use two different kinds at once
  • Pay attention to what the instructions say about how long you should leave the medicine on the hair and on how you should rinse it out
  • After rinsing, use a fine-toothed comb or special “nit comb” to remove dead lice and nits
  • After each treatment, check your hair for lice and nits. You should comb your hair to remove nits and lice every 2-3 days. Do this for 2-3 weeks to be sure that all lice and nits are gone.

All household members and other close contacts should be checked and treated if necessary. If an over-the-counter treatment does not work for you, you can ask your health care provider for a prescription product.

Can head lice be prevented?

There are steps you can take to prevent the spread of lice. If you already have lice, besides treatment, you should

  • Wash your clothes, bedding, and towels with hot water, and dry them using the hot cycle of the dryer
  • Soak your combs and brushes in hot water for 5-10 minutes
  • Vacuum the floor and furniture, particularly where you sat or lay
  • If there are items that you cannot wash, seal them in a plastic bag for two weeks

To prevent your children from spreading lice:

  • Teach children to avoid head-to-head contact during play and other activities
  • Teach children not to share clothing and other items that they put on their head, such as headphones, hair ties, and helmets
  • If your child has lice, be sure to check the policies at school and/or daycare. Your child may not be able to go back until the lice have been completely treated.

There is no clear scientific evidence that lice can be suffocated by home remedies, such as mayonnaise, olive oil, or similar substances. You also should not use kerosene or gasoline; they are dangerous and flammable.

Centers for Disease Control and Prevention

  • Head lice (Medical Encyclopedia) Also in Spanish

Source: https://medlineplus.gov/headlice.html

Head Lice: Symptoms, Treatment and Prevention


A sesame seed-size parasite that feeds on human blood, the head louse (Pediculus humanus capitis) is a nuisance known around the world. These tiny insects infest human hair and can also sometimes be found in the eyebrows and eyelashes. 

An estimated 6 million to 12 million head lice infestations occur each year in the United States among children ages 3 to 11, according to the Centers for Disease Control and Prevention (CDC). While school-age kids are believed to be those most commonly affected by lice, it's possible for people of any age to become infested with these flightless pests. 

Signs & symptoms

Some people with lice never realize they're infested. However, there are several telltale signs that the bugs are present on the scalp, according to the Mayo Clinic. These include:

  • A ticklish feeling on the scalp or neck. 
  • An itchy scalp (the result of an allergic reaction to the bug's saliva).
  • Small red bumps on the scalp, neck and shoulders. 
  • The presence of lice on the scalp. 
  • The presence of nits (lice eggs) on shafts of hair. 
  • Difficulty sleeping, which can lead to irritability.

Some people with lice may also develop sores on their scalp. Such sores are ly the result of bacteria from the person's own body infecting an opening in the skin made by scratching, according to the CDC. Some people may scratch their scalps raw due to the itch and cause skin infections, said Margaret Khoury, a pediatric infectious disease specialist with Kaiser Permanente.

Because head lice are not known to spread disease in the United States, they should not be considered a “medical or public health hazard,” according to the CDC.

Lice are also not indicative of poor hygiene, Khoury said.

However, several studies conducted in recent years in other areas of the world, including Africa, suggest that certain species of head lice are capable of carrying infectious disease. 

One study, outlined in the May 2013 issue of the journal Emerging Infectious Disease, found that head lice in the Democratic Republic of the Congo could spread plague. And another study, outlined in the same journal in May 2014, found that human body lice carrying a pathogen that can cause trench fever — among other diseases — can also inhabit human hair.

Diagnosis & tests

The best way to confirm an active lice infestation is to find a live louse on the head, according to the American Academy of Pediatrics (AAP). Because lice move quickly and avoid light, it's best to check for them after wetting the hair, which some experts say slows the insects down. 

The most effective way to check for lice is to use a louse comb, according to the AAP. In a study published in 2001 in the journal Pediatric Dermatology, researchers found that using a louse comb was four times more effective than simply doing a visual check of the scalp for lice and that checks with the louse comb could be performed two times faster than visual checks. 

Dandruff, dirt and other common debris found in the hair are commonly confused for lice, according to the CDC. Therefore, the best person to perform a head check for lice may be someone trained to identify these parasites, a health care provider or school nurse. 

If no live lice are found on the scalp, finding nits firmly attached to the hair shaft within a quarter inch of the scalp may indicate that a person is infested, according to the CDC. However, it's important to confirm that an infestation of head lice is actually active before pursuing treatment, according to the AAP. 

Nits from previous lice infestations can remain attached to hair shafts, even if no live lice are present on the scalp.

To make future diagnoses of lice easier, as well as to ensure that no living nits remain in the hair, all nits should be removed from the hair, even after the infestation has been treated, according to the National Pediculosis Association (NPA), a nonprofit organization that does not support the use of insecticides to treat lice. 

Treatment & medication

The ideal treatment is one that is “completely safe, free of harmful chemicals, readily available without a prescription, easy to use and inexpensive,” according to the AAP. 

There are several treatment options for those with head lice, including shampoos and creams that contain pediculicides, or insecticides that kill lice, as well as combing the hair with a louse comb that removes lice and nits. Neither one of these treatments options is 100 percent effective at removing all lice or nits from hair.

When choosing a treatment for lice, people should be aware that, in some areas of the United States and Europe, lice have developed resistance to some of the most common pediculicides found in both over-the- counter and prescription lice treatments.

The CDC recommends consulting with a doctor or pharmacist to determine what treatments are best to use.

Khoury, along with the AAP, recommends that lice should first be treated with an over-the counter medication first and move on to prescription medication if the over-the-counter treatment is ineffective or there are potential allergies.

If no resistance to insecticides is suspected, the AAP recommends using products that contain pediculicides known as pyrethrins or the chemical permethrin. However, these chemicals are known to be toxic to humans and should be used with caution, according to the Agency for Toxic Substances and Disease Registry. 

“Permethrin has been the most studied pediculicide in the United States and is the least toxic to humans,” Khoury told Live Science. She added that while pyrethrins are manufactured with natural extracts from chrysanthemum and have extremely low toxicity, those with known allergies to the flower, similar plants, or ragweeds can develop allergic reactions.

If you choose to use a chemical treatment for lice, be sure to follow dosing instructions correctly and consult with your health care provider if you plan to use these treatments on a child under age 2, according to the CDC.

Khoury recommended making sure that you pay special attention to the directions on both over the counter and prescribed medications, including how long the medication should be left in, how it should be washed out, how often doses should be given, approved ages, and any allergy or chemical information.

To minimize exposure to the insecticides found in lice treatment shampoos, rinse the scalp and hair well with cool water after applying these products and try to avoid exposing skin (other than the skin on the scalp) to these products, according to the Canadian Pediatric Society. If you are bathing a child, rinse the treatment the hair over a sink. Do not place the child in a bath as the hair is being rinsed. 

If the lice in your area are resistant to permethrin and pyrethrins, the AAP recommends using a product containing 0.5 percent malathion, another insecticide that is rubbed into the hair and scalp.

Malathion has not been deemed safe or effective to use in children younger than 6, and the product is not safe to use in children younger than 24 months, according to the AAP. Neither malathion nor permethrin and pyrethrins effectively kill all of the egg stages of lice.

This means that these chemicals need to be reapplied to the scalp seven to 10 days after the initial treatment. 

There are also several other chemicals that can be used to treat lice, including lindane, which is available as a cream or a shampoo.

This chemical has been known to cause severe seizures in children and cannot be prescribed to individuals who weigh less than 110 pounds (49.9 kilograms), according to the AAP.

Other chemical treatments have also been linked to dangerous side effects in children, which is why organizations such as the NPA do not recommend the use of chemical treatments for lice.

The manual removal of lice recommended by the NPA can be performed using the same type of fine-toothed louse comb used to check the scalp for lice. Louse combs can be used on wet or dry hair, though some experts suggest that combing out lice and nits is easier on wet hair. Some people may also wish to use a conditioner before combing out the hair, according to the NPA.

Preventing the spread

Once a case of head lice is confirmed, the best way to prevent spread is to thoroughly treat and get rid of the head lice. Avoiding head-to-head contact as much as possible will also help curb an infestation, according to the CDC. 

Although a less-frequent cause of spread, lice can travel from one person to another via shared clothing and accessories, such as hats, brushes and hair accessories. People with lice should avoid sharing these items with others, and should also avoid sharing a bed with siblings or friends. Though rare, lice can spread from person to person through infested upholstery or bed linens. 

Once a person is treated for lice, all bedding, upholstered furniture, carpets, hairbrushes and other items that had direct contact with that person's scalp should be thoroughly cleaned, according to the CDC.

Clothes and bedding can be washed in hot water, hairbrushes and hair accessories can be boiled, rugs or other non-washable items can be dry cleaned, and items that can't be washed or dry cleaned can be stored in airtight containers for several weeks to ensure that live lice and nits do not survive. 

Finally, vacuum carpeted floors and clean all furniture to prevent the spread of lice to others. Measures such as fumigation are not necessary and should be avoided, according to the CDC.

Households with pets do not have to worry about lice infestations moving to the family cat or dog. The CDC says that head lice do not live on pets (lice are species-specific) and are not involved with the spreading of an infestation. 

While some schools follow a “no-nit” policy that requires children with lice to stay at home, the AAP does not recommend such policies. The NPA, however, supports stringent no-nit policies in schools.

Additional reporting by Rachel Ross, Live Science Contributor.

Additional resources

Source: https://www.livescience.com/34732-head-lice-prevention-treatment.html

Head lice and nits


Head lice and nits are very common in young children and their families. They do not have anything to do with dirty hair and are picked up by head-to-head contact.

Head lice are small insects, up to 3mm long. They can be difficult to spot in your hair. Head lice eggs (nits) are brown or white (empty shells) and attached to the hair.

Head lice can make your head feel:

  • itchy
  • something is moving in your hair

The only way to be sure someone has head lice is by finding live lice.

You can do this by combing their hair with a special fine-toothed comb (detection comb). You can buy these online or at pharmacies.

You can treat head lice without seeing a GP.

Treat head lice as soon as you spot them.

You should check everyone in the house and start treating anyone who has head lice on the same day.

There's no need to keep your child off school if they have head lice.

Wet combing

Lice and nits can be removed by wet combing. You should try this method first.

You can buy a special fine-toothed comb (detection comb) online or from pharmacies to remove head lice and nits.

There may be instructions on the pack, but usually you:

  • wash hair with ordinary shampoo
  • apply lots of conditioner (any conditioner will do)
  • comb the whole head of hair, from the roots to the ends

It usually takes about 10 minutes to comb short hair, and 20 to 30 minutes for long, frizzy or curly hair.

Do wet combing on days 1, 5, 9 and 13 to catch any newly hatched head lice. Check again that everyone's hair is free of lice on day 17.

Medicated lotions and sprays

Ask a pharmacist for advice if you have tried wet combing for 17 days, but your child still has live head lice.

They may recommend using medicated lotions and sprays. These kill head lice in all types of hair, and you can buy them from pharmacies, supermarkets or online.

Head lice should die within a day. Some lotions and sprays come with a comb to remove dead lice and eggs.

Some treatments need to be repeated after a week to kill any newly hatched lice.

Check the pack to see if they're OK for you or your child and how to use them.

If lotions or sprays do not work, speak to a pharmacist about other treatments.

Some treatments are not recommended because they're unly to work.

For example:

  • products containing permethrin
  • head lice “repellents”
  • electric combs for head lice
  • tree and plant oil treatments, such as tea tree oil, eucalyptus oil and lavender oil herbal remedies

The charity Community Health Concern has a video about wet combing for head lice.

There's nothing you can do to prevent head lice.

You can help stop them spreading by wet or dry combing regularly to catch them early.

Do not use medicated lotions and sprays to prevent head lice. They can irritate the scalp.

There's no need for children to stay off school or to wash laundry on a hot wash.

Source: https://www.nhs.uk/conditions/head-lice-and-nits/