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How to Kill Head Lice

Where do lice come from?

Like a lice infestation, the exact estimate of how many people get head lice per year is hard to pin down. The Centers for Disease Control and Prevention (CDC) estimates that there are about 6 to 12 million cases each year in the United States among children ages 3 to 11. Since lice can only crawl and survive outside your head for 24 hours, most infestations come from direct head-to-head contact. If someone you know has lice, it’s likely they got it from a friend, family member, or stranger with whom they had close contact. Shared items like hats or brushes can also facilitate an infestation.

Common situations that can lead to the transfer of lice include:

  • being in school, for children
  • sitting in close proximity to others
  • sleeping in the same bed, like during slumber party
  • sharing combs, brushes, or towels

A national survey asked moms about removing lice and found that most did not have accurate facts. Almost 90 percent of moms believe they need to remove nits, and half of moms thought they should apply multiple treatments for head lice. The CDC says that complete removal of nits is unnecessary, though using a lice comb can help. And when it comes to treatment, you should use only one product at a time.

Read on to learn about the most effective ways to kill head lice and how to keep them away.

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First steps

Before you start treatment

As a first line of defense, try a few lifestyle changes and home remedies to combat lice.

Do this

  1. Check other family members for lice.
  2. Wash infected clothes and beddings in a machine with hot water.
  3. Dry clothes with hot air on the highest setting.
  4. Start vacuuming furniture and floors regularly.
  5. If needed, store potentially infected clothes in a plastic bag for two weeks to kill remaining lice and unhatched eggs.

Thankfully, you don’t need to call the pest control. The CDC says there is no need to fumigate your house or treat your pets for lice. Having lice has nothing to do with cleanliness or environment, as they don’t come from the outdoors or your pets.

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Prescription medication

Which medication can you use for head lice?

According to Sanofi Pasteur’s survey, moms who choose prescription treatments were more likely to be satisfied (91 percent) than moms who chose over-the-counter treatments (79 percent).

There are several prescription products you can use to kill head lice. Always start with clean hair, but avoid using combination shampoo and conditioner product before lice treatment application. In addition, the hair should not be rewashed for 1–2 days after the lice medicine is removed. Keep the application on the hair and scalp only. Follow the instructions on your package.

Treatment Application Nit combing? Caution
Malathion (Ovide) Apply this medication to your hair and then rub it into your hair and scalp. A second treatment may be necessary if lice are seen seven to nine days after treatment. Extremely flammable and should only be used for pregnant or breastfeeding women in consultation with a doctor. Not for children less than 6 years of age.
Ivermectin lotion (Sklice) Apply to dry hair and scalp. Rinse after 10 minutes with water. It’s effective with only one treatment. X Not for children under 6 months.
Spinosad topical suspension (Natroba) Apply to dry hair and scalp. Rinse after 10 minutes with water. Repeated treatment is typically not necessary. Not necessary Not for children under 6 months of age.
Benzyl alcohol lotion (Ulesfia) Apply this lotion to your scalp and dry hair for 10 minutes, completely saturating the scalp and hair. Rinse with water. Repeat treatment is needed, as it kills the lice but not the eggs. Not for children under 6 months. Safe in pregnancy and breastfeeding.
Lindane Apply shampoo to dry hair and scalp. Leave for four minutes before adding water for a lather. Rinse afterward. Retreatment should be avoided. X Lindane causes serious side effects. Use only if other prescriptions fail. Not for premature infants, those with HIV, women who are pregnant or breast-feeding, children, the elderly, or those weighing less than 110 pounds.
 

Possible side effects of prescription treatment include:

  • dandruff
  • a burning sensation where you apply the medication
  • eye redness
  • skin, scalp, and eye irritation
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OTC treatment

Over-the-counter treatments for head lice

If you’re looking at over-the-counter (OTC) treatments for lice, keep an eye out for these ingredients:

Pyrenthrins: This is a natural extract from chrysanthemums. It’s safe for children 2 years old and older. But this ingredient only kills live lice, not eggs (nits). You will need a second treatment after nine to 10 days if existing eggs have hatched. This should not be used by any individuals allergic to chrysanthemums or ragweed.

Permethrin lotion, 1 percent (Nix): This is a synthetic version similar to natural pyrethrins. It only kills live lice and not eggs. You will likely need to apply a second treatment after nine to 10 days to kill newly hatched lice. Permethrin is safe for children 2 months and older. Talk to your doctor if you still see lice after full treatment. Your doctor can help prescribe something stronger.

OTC treatments for kids

Since children under 2 should not use most OTC lice-removal products, try simply using a fine-toothed comb — or a special nit comb — when your child’s hair is wet. Metal combs are more effective than plastic. Repeat this combing every three to four days for no less than two weeks. Ask your pediatrician if combing should be used in conjunction with other treatments for your young child.

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After treatment

What to do after treatment

After each treatment, you should continue checking the hair to remove nits or lice.

Remember to:
  • remove dead or live lice with a fine-toothed comb eight to 12 hours after treatment
  • avoid using regular shampoo one to two days after
  • continue checking for two to three weeks for nits and lice
  • soak combs and brushes in boiling water for five to 10 minutes

What if the treatment doesn’t work?

Sometimes treatment doesn’t work because lice are resistant. Other times it’s because someone didn’t follow the instructions carefully enough. OTC products don’t kill nits, so application is a matter of timing. It’s also possible for someone to become infested again. Talk to your healthcare provider if a full course of treatment doesn’t work. They’ll be able to help prescribe a different medication and recommend prevention tips.

Read more about lice prevention »

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Home remedies

Do natural home remedies work?

For people interested in natural home remedies, there are many options. Most alternative treatments, like olive oil, mayonnaise, or butter, don’t have enough evidence for suffocating lice. Some treatments like tea tree oil show promise, but they may require more time and more frequent applications. Shaving the head does also get rid of lice, but it doesn’t prevent them.

If you’re looking for fast and easy results, prescription products may be a better choice. Talk to your healthcare provider to find out which treatment is the most effective, safe, and easy to use.

A parent’s guide to lice outbreaks »

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