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Lice

Medically reviewed by Drugs.com. Last updated on Jun 30, 2022.

Overview

Lice are tiny, wingless insects that feed on human blood. Lice spread from person to person through close contact and by sharing belongings.

There are three types of lice:

Unless treated properly, lice can become a recurring problem.

Head lice

Head lice occur on the scalp and are easiest to see at the nape of the neck and over the ears. Small nits (eggs) resembling tiny pussy willow buds about the size of dandruff flakes are visible on hair shafts.

Symptoms

Common signs and symptoms of lice include:

When to see a doctor

See your health care provider if you suspect you or your child has lice. Things often mistaken for nits include:

Head lice

Head lice feed on blood from the scalp. The female louse lays eggs (nits) that stick to hair shafts.

Causes

Lice feed on human blood and can be found on the human head, body and pubic area. The female louse produces a sticky substance that firmly attaches each egg to the base of a hair shaft. Eggs hatch in 6 to 9 days.

You can get lice by coming into contact with either lice or their eggs. Lice can't jump or fly. They spread through:

Prevention

It's difficult to prevent the spread of head lice among children in child care and school settings. There's so much close contact among children and their belongings that lice can spread easily. The presence of head lice isn't a reflection of hygiene habits. It's also not a failure on the parent if a child gets head lice.

Some nonprescription products claim to repel lice. But more research is needed to prove their safety and effectiveness.

Many small studies have shown that ingredients in some of these products — mostly plant oils such as coconut, olive, rosemary and tea tree — may work to repel lice. However, these products are classified as "natural," so they aren't regulated by the Food and Drug Administration (FDA). Their safety and effectiveness haven't been tested to FDA standards.

Until more research proves the effectiveness of head lice prevention products, the best approach is simply to take thorough steps to get rid of lice and their eggs if you find them on your child. In the meantime, these steps can help prevent lice:

However, it's not realistic to expect that you and your child can avoid all contact that may cause the spread of lice.

Your child may have nits in his or her hair but may not develop a case of head lice. Some nits are empty eggs. However, nits that are found within 1/4 inch (6 millimeters) of the scalp typically should be treated — even if you find only one — to prevent the possibility of hatching.

Diagnosis

During an exam, a health care provider may use a magnifying lens to look for lice. The provider may also use a special light, called a Wood's light, to check for nits. This light makes the nits easier to spot by making them look pale blue.

Head lice

A health care provider may diagnose head lice after finding a live young or adult louse in the person's hair or on the scalp, or after seeing one or more nits on hair shafts found within 1/4 inch (6 millimeters) of the scalp.

Body lice

A health care provider may diagnose body lice if they find eggs or crawling lice in clothing seams or on bedding. You can see a body louse on skin if it crawls there to feed.

Pubic lice

A health care provider may diagnose pubic lice when they see moving lice or nits on hair in the pubic area or on other areas of coarse hair, such as chest hair, eyebrows or eyelashes.

Treatment

Use drugs that treat lice only as directed. Applying too much can cause red, irritated skin.

Head lice

Head lice treatment may involve:

Body lice

If you have body lice, first bathe with soap and water. After bathing, apply permethrin (Nix) to the affected areas before bedtime and then shower in the morning. Repeat this treatment nine days after the first application.

Also take other measures to get rid of body lice. Wash clothing and bedding with hot, soapy water — at least 130 F (54 C) — and dry them at high heat for at least 20 minutes. Vacuum the floors and furniture. And seal unwashable items in an airtight bag for two weeks.

Pubic lice

Pubic lice can be treated with many of the same nonprescription and prescription treatments used for head lice. Carefully follow the package instructions. Talk to your health care provider about treatment of lice and nits on eyebrows or eyelashes.

Self-care

Whether you use nonprescription or prescription shampoo to kill lice, much of the treatment involves self-care steps you can take at home. These include making sure all the nits are removed and that all clothing, bedding, personal items and furniture are free of lice.

In most cases, killing lice that are on you isn't difficult. The challenge is getting rid of all the nits and avoiding contact with other lice at home or school.

Lifestyle and home remedies

You can get rid of lice with a patient, detailed approach that involves cleaning yourself or your child and any personal belongings that may contain lice.

These steps may help you get rid of lice:

One thing you don't need to worry about is your household pets. Lice prefer people to pets. So your pets don't need any treatment for lice.

Alternative medicine

Many home or natural remedies, such as mayonnaise or olive oil, are used to treat head lice. But there's little to no evidence of their effectiveness.

A special machine that uses hot air to dehydrate head lice and their eggs is another alternative treatment method. The machine requires special training and is currently available only at professional lice treatment centers.

A regular hair dryer can't be used to do this at home because it's too hot and could burn the scalp. The machine that dehydrates lice is cooler than most hair dryers but has a much higher flow rate to kill the lice by drying them out.

Preparing for an appointment

Often, you can get rid of lice with nonprescription treatments and by properly washing household items that had lice on them, such as sheets, towels and clothes. If these steps don't work, see your health care provider.

Here's some information to help you get ready for your appointment and what to expect from your provider.

What you can do

Some basic questions to ask your health care provider about lice include:

In addition to the questions that you've prepared to ask your health care provider, don't hesitate to ask questions during your appointment when you don't understand something.

What to expect from your doctor

Your health care provider is likely to ask you a number of questions, such as:

What you can do in the meantime

If you think or know you have lice, avoid sharing personal items, bedding, towels or clothing. Bathe and follow self-care measures, including washing items in hot water.

If you think or know you have pubic lice, also avoid sexual activity until you've been treated.

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