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Head Lice

What You Need to Know

  • Head lice spread from head-to-head (or hair-to-hair) contact with someone who actively has head lice. Head lice can also spread from sharing personal items that come in contact with a person’s head.

  • Head lice are common among school-aged children, but anyone can get head lice.
    Head lice are more likely to spread at home, daycare, or at a friend’s house than at school.

  • Over-the-counter and prescription medications are used to treat head lice. Combing hair to remove nits is also an important way to get rid of head lice.

  • To prevent getting head lice, avoid head-to-head contact with someone who has head lice, and do not share hats, scarves, coats, and other personal items. Also, do not lie down on beds, pillows, carpets, or stuffed animals that have recently been in contact with someone who has head lice.

What are head lice?

Head lice are small insects that live in people's hair and feed on human blood. Lice glue their eggs (also called "nits") at the base of hairs on the head, close to the scalp. Nits hatch and grow into adult head lice, which are about the size of a sesame seed and are grayish-white in color. Head lice spread from person to person and do not survive very long away from a person's head. Head lice do not spread disease. 

Louse in hair     Nit, nymph, and adult head louse in comparison to a penny

Image source: CDC

Where are head lice found?

Head lice and nits are most commonly found on a person's scalp and in the hair, usually behind the ears and near the neckline. Nits that are found close to the scalp (less than ¼ inch from the scalp) usually contain living lice. Nits glued to hair further away from the scalp are usually empty (meaning the lice have already hatched) or are dead. 

What are the signs and symptoms of head lice?

Nits in hair

The most common symptoms of head lice include:

      • A "tickling" feeling of something moving in the hair

      • An itchy head or scalp

      • Irritability, frequent scratching, or trouble sleeping, as head lice are most active at night

Signs that a person has head lice include:

      • Nits stuck on the hair, especially near the scalp (not to be confused with flakes, dirt, or dandruff that can easily be brushed away)

      • Lice crawling in the hair

Pediculosis is the term used to describe having active head lice, meaning lice are found crawling on the head, and nits are found less than ¼ inch from the scalp. Medications used to treat lice are known as pediculicides.

Head lice are very small, move quickly, and avoid the light, so they may be hard to find in the hair. Combing hair with a nit comb (a metal comb with long teeth) may help in finding both nits and head lice in hair. If you're still not sure if you or a child has head lice, talk to a doctor or nurse.  

How do head lice spread?

Head lice usually spread from head-to-head (or hair-to-hair) contact with a person that already has head lice. Head lice can also spread by sharing combs, hats, clothes, hair clips, scarves, or other personal items that come in contact with a person's head. Head lice are more likely to spread between children during sleepovers, play dates, and family gatherings, and less likely at school. 

Touching heads with other people and sharing personal items can spread head lice.

Two young people touching heads while taking a selfie.

Who can get head lice?

Head lice are most common among school-aged children, but anyone can get head lice. Having head lice isn't a sign of poor hygiene or being dirty.

How can I get rid of head lice?

Over-the-counter products and medications prescribed by a healthcare provider are available for the treatment of head lice. To learn more about treatment options, please visit the U.S. Centers for Disease Control and Prevention (CDC) head lice treatment webpage.

Only people with active lice (crawling lice found on the head and nits less than ¼ inch from the scalp) should be treated. People with active lice in the same household and close contacts should be treated at the same time so that lice do not continue to spread.

It is important to follow the instructions on the product label or directions given by a healthcare provider to treat head lice. Some medications may not kill nits, so a second or third treatment may be required. Retreatment is only recommended if active lice are found 7-9 days after the last treatment.

There is no proof that mayonnaise, olive oil, butter, petroleum jelly, or other similar items will suffocate or kill head lice. There is also no proof that organic or “natural” products kill head lice.

Nit comb

Nit combing is also important if using medication that does not kill nits (most over-the-counter products and some prescribed medications kill only active lice, not nits). Hair should be combed every 2–3 days with a nit comb for two weeks or until nits are no longer found. Nit combs should be metal and have long teeth that are close together. Several nit comb brands are available at your local pharmacy. Metal flea combs from pet stores may also be used.

Should I treat or clean my home if someone in my home has head lice?

Clothes, bedding, and towels used by a person with head lice two days before treatment should be washed in hot water and dried on the hot cycle to kill any lice. Other items that cannot be washed or dry-cleaned can be placed in a sealed plastic bag for two weeks to kill any lice or nits on those items. Combs, brushes, hair bands, and hair clips should also be soaked in hot water (130°F or hotter) for 5–10 minutes.

Carpet and furniture where a person with head lice has sat or laid down can be vacuumed, but pesticide treatment of the home is not necessary. Head lice don't live very long away from a person's head.

How can I prevent getting he​ad lice?

The best way to prevent getting head lice is to not touch heads with someone that has head lice, including during play or other activities at home, school, or other places. It's also important to avoid sharing personal items (especially if they touch a person's head) with someone that has head lice. Do not lie down on beds, pillows, carpets, or stuffed animals that have recently been in contact with someone who has head lice.

You may not be able to tell if someone has head lice or not, so it's best to not share personal items that could spread head lice from one person to another. These items include hats, scarves, coats, sweaters, brushes, hair accessories, headphones, or towels.  

Educational Materials
Sample of CDPH head lice flyer
Sample of CDPH nit combing guide
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