What are head lice?
Head lice are tiny insects that live close to the scalp where they lay and attach their eggs.
Every year, millions of children get head lice. They are common because they can spread anytime a child's head comes into contact with another child's head or hair. For example, lice can spread at school or day care, on a playground, during sports, or at slumber parties.
Lice can live a month on the head. But they can only survive 1 to 2 days without the warmth of a person's head. And they can't hop or jump.
It's common to get lice from direct contact with someone's head. It's not common to get lice from a bed, pillow, couch, or carpet.
Getting lice can be inconvenient. But lice aren't dangerous, and they don't spread disease or have anything to do with how clean someone is. And you can learn how to treat lice at home.
How are head lice diagnosed?
The first sign of head lice may be an itchy feeling on the scalp. But not everyone has itching, and not all itching means you have lice.
A health professional can check for lice and their eggs (called nits). But you can also check your child's scalp for lice and nits.
To check for lice, use a fine-toothed comb. Part small sections of hair in a place with good light. If you have a magnifying glass, it can help you see the lice and nits in the hair.
- Nits look like tiny yellow or white dots attached to the hair, close to the scalp. They're often easier to see than live lice. Nits can look like dandruff. But you can't pick them off with your fingernail or brush them away.
- Live lice are tan to grayish white. They're about the size of a sesame seed. It may be easiest to find them at the base of the scalp, the bottom of the neck, and behind the ears.
How are they treated?
It's important to treat head lice, because they won't go away without treatment.
There are several over-the-counter medicines that kill lice. Most of them are creams or shampoos that you put on your scalp for a certain amount of time. There are also prescription medicines. Each type of medicine is a little different. It's important to use any medicine correctly and to choose a medicine that is safe for you.
You can also talk to the pharmacist to understand how to use a medicine and make sure that it is safe for you.
- Some medicines need just one treatment. Others require follow-up treatments.
- Children should be able to keep going to school as soon as they begin treatment. You shouldn't have to wait until all nits are gone. Although some schools have "no-nit" polices, most doctors agree that children should be allowed to go back to class after the start of treatment.
- Check the scalp for live lice 48 hours after treatment. If you find some, try a different type of treatment. It's possible that the lice in your area are resistant to the first treatment you tried.
- After treatment, you'll still see the shell of the nits attached to the hair. You don't have to remove them. But you can use a comb to remove them, if it makes you or your child feel better.
- Sometimes the skin itches for a week or more after treatment.
How can you prevent head lice from spreading?
Head lice are contagious. That means they can easily spread from one person to another. But you can take steps to prevent that.
- Check everyone in your home for lice. You don't have to worry about pets. They can't get lice.
- Teach your children not to share anything that comes into contact with hair. For example, don't share hair bands, barrettes, towels, hats, combs, or brushes.
- You don't need to spend a lot of time or money deep cleaning your home. But it is a good idea to:
- Soak hairbrushes, combs, barrettes, and other items for 10 minutes in hot water [at least 130°F (54.4°C)].
- Vacuum carpets, mattresses, couches, and other upholstered furniture.
- Machine-wash clothes, bedding, towels, and hats in hot water [at least 130°F (54.4°C)]. Dry them in a hot dryer. If you don't have access to a washing machine, instead you can store these items in a sealed plastic bag for 14 days.
When should you call a doctor?
Call your doctor now if:
- You have signs of infection, such as:
- Increased pain, swelling, warmth, or redness.
- Red streaks leading from the area.
- Pus draining from the area.
- A fever.
Call your doctor if:
- You are not getting better as expected.
- Your symptoms get worse.
Current as of: December 12, 2018
Author: Healthwise Staff
Adam Husney MD - Family Medicine
E. Gregory Thompson MD - Internal Medicine
Kathleen Romito MD - Family Medicine
John Pope MD - Pediatrics