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Head Lice

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Head lice: Overview

Also called Pediculus humanus capitis

Having head lice does not mean you are dirty. Most people get head lice when they have head-to-head contact with someone who has head lice. Head-to-head contact lets the lice crawl from one head to another head. The lice do not care whether the person has squeaky-clean hair or dirty hair. The lice are looking for human blood, which they need to survive.

Millions of people get head lice each year. Head-lice infestations are especially common in schools. In the United States, it is believed that about 6 to 12 million children between 3 and 12 years of age get head lice each year.

Head lice are not known to spread disease, but having head lice can make your scalp extremely itchy. If you scratch a lot, it can cause sores on the scalp that may lead to an infection. Some people lose sleep because the itch is so intense.

Treatment, which most people can do at home, usually gets rid of head lice. If you have trouble getting rid of the lice or have an infection from scratching, you should see a dermatologist.

Head lice: Signs and symptoms

Signs and symptoms of head lice include:

  • Itchy scalp.
  • Scratching. Some people scratch so much that the scalp — and sometimes the back of the neck — become red and irritated.
  • Crawling sensation. People often feel something crawling on the hair or scalp.
  • Seeing bugs. These look like light-brown sesame seeds crawling on the hair, skin, or clothing.
  • Finding lice eggs (nits). The eggs are yellow, brown, or tan and about the size of a pinhead. These seem glued to the hair. If the eggs have hatched, you will see clear shells.
  • Swollen lymph nodes (many people call “glands”) in the neck.
  • Pink eye. This is a common eye infection.

An itchy scalp is the most obvious symptom of head lice, but that alone does not mean you have head lice. Other more common things like dandruff and eczema also can make the scalp itch.

You also can have head lice and not itch. It sometimes takes a few weeks after the lice arrive for the scalp to start itching. 

Head lice: Who gets and causes

Who gets head lice?

Anyone can get head lice. In the United States, children in preschool and elementary school are most likely to get head lice. Children can spread the lice to their parents, caretakers, and others in their households.

Girls seem more likely than boys to get head lice. This may be because girls tend to have more frequent head-to-head contact than do boys. You’ll often see girls in head-to-head contact at school, on the playground, at camp, or at a slumber party.

What causes head lice?

Head-to-head contact is the most common way to get head lice. The lice move from one person to the next by crawling. They cannot fly or jump. It may seem like lice can jump because they are tiny and move quickly.

Head lice actually crawl everywhere. They crawl from person to person and on to objects that come into contact with human hair such as hats and towels.

Because head lice crawl onto objects that have touched the human head, it is possible to get head lice by sharing everyday objects infested with lice such as hats, scarves, coats, hair accessories, brushes, combs, and towels. Resting your head on a bed, pillow, couch, chair, or rug that someone with head lice used is another way to get head lice.

Head lice: Diagnosis and treatment

Check for and treat head lice like a pro with these dermatologists' tips.

Diagnosing head lice at home

If you are concerned that someone has head lice, you can usually diagnose this at home. You will need 2 common items:

  • Bright light.
  • Fine-tooth comb or lice comb.

What to do: You can find head lice by following these 3 steps:

  • Wet the hair of the affected child or adult, if possible. Some people think it’s easier to see the lice when the hair is wet. This also prevents the lice from scurrying away.
  • Sit the affected child or adult under a bright light.
  • Separate hair into sections. Beginning at the scalp, slowly comb outward through the hair section by section.

What to look for: You are looking for adult lice and their eggs (called nits). You’re more likely to see nits than adults because nits are firmly attached to the hair and do not move.

As you comb through the hair, look closely at the hair behind the ears and around the nape of the neck. These are likely places to find lice and nits.

If the person has adult lice or nits, you will see the following:

  • Adult lice: These look like one or more light-brown objects that resemble sesame seeds, often moving quickly. You can find these on the scalp or the hair.
  • Eggs: These are yellow, brown, or tan objects that look like tiny seeds and appear to be cemented to individual hairs close to the scalp. If an egg has hatched, the seed-like object will be clear.

When looking closely at the scalp and hair, it is important to know that kids — and adults — can have all kinds of stuff in their hair. You may see sand, dirt, lint, or dandruff. All of these comb out easily. Nits seem cemented to the hair and very difficult to remove.

Treating head lice at home

There are several products that you can buy at your local drug or grocery store to get rid of head lice and their nits. These are available without a prescription. Dermatologists offer the following tips for using these products:

First treatment

  • Carefully read and follow the directions. Using a lice shampoo usually involves lathering a shampoo into the hair and leaving the shampoo on for a few minutes before rinsing.
  • Apply the product to the head of a fully dressed person, and rinse the product out with a spray hose or running water from a sink. These products are not meant for use while taking a shower or bath. You want to limit the amount of skin that the product touches.
  • Use only one product. Using two products meant to treat head lice can be harmful. If two different products are necessary, your dermatologist can tell you which ones can be combined.
  • Use the amount stated on the product. Using more can be harmful.
  • Use the lice comb that comes with the shampoo. The teeth on a lice comb are closer together than the teeth on a regular comb. Placing the teeth closer together makes it easier to remove the lice and their nits.
  • Look at the hair 8 to 12 hours after treatment. If the lice seem as active as they were before the treatment, the medicine may not be working. Do not treat again. Talk with your dermatologist. A different lice medicine may be necessary.

The next day

If the medicine seems to be working, you’ll want to:

  • Wait 2 days to wash your hair. This lets the medicated product continue to work.
  • Continue to comb through the hair with the lice comb once a day. Doing this for 2 to 3 weeks helps to ensure that you get rid of the lice.

7 to 9 days after the first treatment

  • Retreat as recommended on the package. Retreatment is generally recommended with all products you can buy without a prescription. Retreatment is usually done 7 to 9 days after the first treatment. The lice shampoos often are more successful at killing the adult lice than the nits, so retreatment helps to kill any surviving lice that hatched after the first treatment. No approved treatment for head lice can kill all the eggs during the first treatment.
  • After applying the second treatment, comb through the hair with the lice comb.
  • Wait 2 days to wash the hair.
  • Continue to comb through the hair with the lice comb once a day. Do this for 2 weeks, checking for lice and nits.

How to improve at-home treatment for head lice

Use a lice comb: Using a lice comb can improve the effectiveness of treatment. It also is important to use a lice comb when school policy requires that a child be “nit free” before returning to school.

If all this seems like too much trouble, another treatment option is to shave the scalp bald.

Treat family and friends: It is very common for close family and friends to get head lice. Dermatologists recommend that you check everyone for head lice. You do not want to treat anyone who does not have head lice; however, you should check everyone every day for 10 to 15 days.

When to see a dermatologist about head lice

If the at-home treatment does not work or this seems more than you can handle, you should see a dermatologist for treatment. Your dermatologist may recommend a product that you can buy without a prescription or a prescription medicine. The U.S. Food and Drug Administration (FDA) has approved the following prescription medicines to treat head lice:

Benzyl alcohol lotion: Approved to treat head lice in people 6 months of age and older, this medicine is applied to dry hair. When using this treatment, you want to saturate the scalp and hair. After 10 minutes, it’s time to thoroughly rinse off the medicine. Because benzyl alcohol kills the lice but not their eggs, it’s important to repeat the treatment in 7 days.

When using this medicine, you’ll need to comb the hair for nits.

Women who are pregnant or breastfeeding can use this medicine to treat head lice.The most common side effect is irritated skin.

Ivermectin (eye-ver-mec-tin) lotion: Approved to treat head lice in people 6 months of age and older, this medicine offers convenience. Invermectin treats most head lice with just one use and without the need to comb nits out of the hair.

Side effects include itchy skin, eye irritation (if the medicine gets in an eye), and a burning sensation on the skin. All are temporary.

Malathion (mal-uh-THIGH-on) lotion: Approved to treat people ages 6 years of age and older, malathion works by paralyzing and killing the lice and their eggs. This is very potent medicine, so be sure that you:

  • Keep the medicine away from everyone’s eyes. If the medicine gets in someone’s eyes, flush the eyes right away with lots of water for several minutes.
  • Do NOT smoke while using this medicine. If anyone in the room smokes while this medicine is being used, a fire can start. Leave cigarettes, cigars, and other things that you can smoke in another room.
  • Keep the medicine away from flames. You want to use malathion in a room without a stove or fireplace. Because malathion can easily cause a fire, even unlit lighters and camp stoves should NOT be in the room where you’ll use malathion. If you’re using malathion outdoors, be sure a camp fire is NOT burning.
  • Keep all electrical appliances that produce heat turned off. Using this medicine while a blow dryer, iron, curling iron, or space heater is running nearby can start a fire.

When used as directed, malathion is safe and effective. It can irritate the skin a bit as it works. Some people get dry hair or their skin can burn or sting. These side effects are temporary. 

Spinosad suspension: This medicine is approved to treat head lice in people 6 months of age and older. It has been found to be safe and effective when used as directed.Like ivermectin lotion:

  • Most people need to apply this medicine only once.
  • Nit combing is not necessary.

You will need to check the scalp 7 days after treatment. If crawling lice are seen be sure to tell your dermatologist. You may need to repeat the treatment.

When using prescription treatment for head lice, you still need to wash clothing, towels, and sheets that the person with head lice has used since getting head lice. Wash everything in hot water.

May be prescribed if other treatments fail or cannot be used

Lindane shampoo: This medicine has been approved by the U.S. Food and Drug Administration (FDA) to treat head lice. Approved to treat head lice, this treatment is prescribed when other treatments do not work. It is essential to use lindane shampoo only as directed. It can be toxic when misused.

Treating your home for head lice

Whether you treat at home or see a dermatologist, you must also treat your home. To avoid another infestation, you should clean the following items:

Brushes and combs

  • Soak combs and brushes that a person with head lice used. Soak these in hot water, 130 degrees Fahrenheit or hotter, for 10 minutes.

Sheets, pillowcases, clothes, blankets, and towels

  • Place all items that touched the person’s head during the past 2 days in a washing machine and wash in hot water.
  • Dry all machine-washed items in a hot dryer, using the hottest setting. Dry for at least 10 minutes.

Stuffed animals and pillows

  • Place items that cannot be machine washed in a hot dryer and run the dryer on the hottest setting for 20 to 30 minutes.

Other personal items

Hair accessories, helmets, headphones, and other personal items can become infested with head lice. If a person with head lice has touched any of these items during the past 2 days, you can kill the lice on these objects by:

  • Sealing the objects in plastic bags.
  • Placing the plastic bags in the freezer overnight or keeping the bags sealed for 2 weeks.

Two weeks is the amount of time needed for adult lice and newly hatched lice to die when hot water, dryer heat, and freezing are impractical.

Furniture, carpets, and floors

  • Vacuum these thoroughly to pick up any hairs the person with head lice has shed. Everyone normally loses about 50 to 100 hairs a day.

Outcome

Two treatments (spaced 7 to 9 days apart) often get rid of head lice. If your child or someone else in your family still has head lice after a few weeks, it means that the treatments did not work or the person got lice again. Make an appointment to see a dermatologist for help getting rid of the head lice. With proper treatment, it is possible to get rid of head lice.

Head lice: Tips for managing

Head lice are common, and it is easy for children to pick up head lice at school and other places where they play. There are a few things you can do to reduce the risk of your child getting head lice.

Teach your child to stop sharing things that touch the head. Brushes, combs, hair accessories, hats, helmets, scarves, towels, and even earbuds offer head lice a good place to hang out until they can crawl onto a human.

When someone has head lice, tell your child not to touch couches, chairs, pillows, rugs, and beds that a person who has head lice uses.

If your child’s school reports a head lice infestation, there are a few things you can do to catch head lice early.

  • Check your child’s hair.
  • Inspect household items that can get infested with lice and nits — towels, rugs, and bedding.
  • Look carefully at the clothes your child has worn during the past 2 days for lice and their eggs.
  • Reinforce the message to stop sharing anything that touches the head.
  • Tell your child to stop head-to-head contact with other kids until the school is free of lice.

Related resources:

Head lice
Information from the Centers for Disease Control.

Treating head lice
Consumer health information from the U.S. Food and Drug Administration (FDA), which includes FDA-approved treatments for head lice.

References:

Burkhart CN, Burkhart CG. “Fomite transmission in head lice.” J Am Acad Dermatol 2007; 56(6):1044-1047.

Canyon, DV, Speare R, et al. “Spatial and kinetic factors for the transfer of head lice (Pediculus capitis) between hairs.” J Invest Dermatol 2002; 119(3):629-631.

Frankowski BL, Bocchini JA. “Head Lice.” Pediatrics. 2010; 126(2):392-403.

Jacobson CC, Abel EA. “Parasitic infestations.” J Am Acad Dermatol 2007; 56(6):1026-1043.

Ko CJ, Elston DM. “Pediculosis.” J Am Acad Dermatol 2004; 50(1):1-12.

Di Stefani A, Hoffman-Wellenhof R, Zalaudek I, et al. “Letters to the editor: Dermoscopy for diagnosis and treatment monitoring of pediculosis capitis.”  J Am Acad Dermatol 2006; 54(5):909-10.

Early J and MacNaughton H. “Ivermectin Lotion (Sklice) for Head Lice.” Am Fam Physician. 2014 Jun 15;89(12):984-986.

Frankowski BL, Bocchini JA. “Head Lice.” Pediatrics 2010; 126(2):392-403.

Gunning K, Pippitt K, et al. “Pediculosis and Scabies: A Treatment Update.” Am Fam Physician. 2012 Sep 15;86(6):535-41.

Heymann, WR. “Head lice treatments: Searching for the path of least resistance.” J Am Acad Dermatol 2009; 61(2):323-4.

Jones KN, English JC, “Review of Common Therapeutic Options in the United States for the Treatment of Pediculosis Capitis.” CID 2003; 36(1):1355-61.

Ko CJ, Elston DM. “Pediculosis.” J Am Acad Dermatol 2004; 50(1):1-12

Miteva M, Tosti A. “Hair and scalp dermatoscopy.” In Press, J Am Acad Dermatol. 2012; 67(5):1040-8.

U.S. Food and Drug Administration, “Treating Head Lice.” FDA Consumer Health Information. July 2009.1-2.

Frankowski BL, Bocchini JA. “Head Lice.” Pediatrics 2010; 126(2):392-403.

Ko CJ, Elston DM. “Pediculosis.” J Am Acad Dermatol 2004; 50(1):1-12

U.S. Food and Drug Adminstration, “Treating Head Lice.” FDA Consumer Health Information. July 2009.1-2.

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