• Topic Overview
• Cause
• Symptoms
• What Happens
• What Increases Your Risk
• When To Call a Doctor
• Exams and Tests
• Treatment Overview
• Prevention
• Home Treatment
• Medications
• Other Treatment
• Other Places To Get Help
• Related Information
• References
• Credits

Topic Overview

What are lice?

Lice are tiny insects that live on humans and feed on blood. When a large number of lice live and multiply on a person, it is called an infestation.

Three different kinds of lice live on humans:

• Head lice are usually found in hair, most often on the back of the neck and behind the ears. Head lice are common in preschool and elementary school-age children. Adults can get them too, especially adults who live with children.
• Pubic lice, also called crabs, are usually found in the pubic area. But they may also be found on facial hair, on eyelashes, on eyebrows, in the armpits, on chest hair, and, rarely, on the scalp.
• Body lice live and lay eggs (nits) in the seams of clothing. The lice are on the body only when they feed.

What causes a lice infestation?

Lice spread easily from one person to another through close contact or through shared clothing or personal items (such as hats or hairbrushes). A louse cannot jump or fly.

What are the symptoms?

The most common symptom of lice is itching. There are different symptoms, depending on which type of lice you have.

• Head lice may not cause any symptoms at first. Itching on the scalp may start weeks or even months after lice have started to spread. Scratching can make the skin raw. The raw skin may ooze clear fluid or crust over, and it may get infected.
• Pubic lice cause severe itching. Their bites may cause small marks that look like bruises on the torso, thighs, or upper arms. If pubic lice get on the eyelashes, the edges of the eyelids may be crusted. You may see lice and their eggs at the base of the eyelashes.
• Body lice cause very bad itching, especially at night. Itchy sores appear in the armpits and on the waist, torso, and other areas where the seams of clothes press against the skin. The lice and eggs may be found in the seams of the person's clothing but are generally not seen on the skin.

Frequent scratching can cause a skin infection. In the most severe cases of head lice, hair may fall out, and the skin may get darker in the areas infested with lice.

How is a lice infestation diagnosed?

A doctor can usually tell if you have lice by looking closely for live lice or eggs in your hair. The doctor may also comb through your hair with a fine-toothed comb to help detect lice. He or she may look at the lice or eggs under a microscope.

Your doctor can also find pubic lice and body lice by looking closely at your body or your clothing.

How is it treated?

Lice won't go away on their own. Be sure to do all you can to treat lice and to prevent the spread of lice.

The most common treatment is an over-the-counter or prescription cream, lotion, or shampoo. You put it on the skin or scalp to kill the lice and eggs. In some cases, you may need treatment a second time to make sure that all the eggs are dead. If two or more treatments don't work, your doctor may prescribe a different medicine.

It's also important to wash clothing and bedding in hot water to help get rid of lice.

Some people have an allergic reaction to lice bites that causes itching for 7 to 10 days after the lice and eggs have been killed. Steroid creams or calamine lotion can relieve the itching. If you have severe itching, you can try antihistamine pills. But don't give antihistamines to your child unless you've checked with the doctor first.