Lice
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
- Body lice
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. He or she may look at the lice or eggs under a microscope to be sure.
Your doctor can also find pubic lice and body lice by looking closely at your body or your clothing.
How is it treated?
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 pill called ivermectin.
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.
Learning about lice:
Being diagnosed:
Getting treatment:
Living with a lice infestation:
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| Author: | Debby Golonka, MPH Ralph Poore | Last Updated: November 24, 2006 |
| Medical Review: | Kathleen Romito, MD - Family Medicine Michael J. Sexton, MD - Pediatrics Thomas Emmett Francoeur, MDCM, CSPQ, FRCPC - Pediatrics | |
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