Am Fam Physician. 2012;86(6):1-2
See related article on pediculosis and scabies.
What are lice and scabies?
Lice are small insects that live on the skin. They are often connected to hair on the scalp or in the pubic area. When you have lice, it is called pediculosis. Scabies is a condition caused by mites, which are tiny, insect-like animals that dig under the skin. Both conditions cause itching.
How do I know if I have lice or scabies?
If you itch on your scalp or other hairy parts of your body, and the itching happens at all times of day, it is more likely to be lice. Scabies usually is not on the head or neck area, and the itching is often worse at night.
If you think you or your child might have lice, look at the scalp closely. Lice are hard to see, so it is best to look for the lice eggs (also called nits), which are a light brown color. They are attached to the hair shaft next to the scalp, often behind the ears or on the neck.
Scabies is harder to see. The mites usually dig into the skin between the fingers, or around the ankles and wrists. The areas where they dig may look like wavy, red, raised lines on the skin.
How are lice treated?
Treatment is only needed if you see live lice. Lice can be killed with special lotions and shampoos that you can buy over the counter. Two brands are Nix and Rid. Follow the directions carefully. Rid should be put on dry hair at the scalp. Nix should be put on damp hair at the scalp. Both should be left on for 10 minutes and then rinsed out.
Comb the hair with a special fine-toothed comb to remove lice eggs. You can comb more than once, but do not use the treatment again for at least seven days. Make sure that there are still lice on the scalp before you treat again. Sometimes there will be itching even if there are no lice. Empty egg sacs are sometimes found in the hair for a few weeks after treatment. This does not mean that you need more treatment.
Be sure to wash your clothing, bed sheets, and pillows in very hot water. If they are unable to be machine washed, put them in a sealed plastic bag for two weeks to kill the lice and lice eggs. Also, vacuum your house thoroughly. You do not need to use chemical sprays.
How is scabies treated?
See your doctor right away if you think you have scabies. He or she will prescribe a cream to use on your body from the neck down. Make sure to follow the directions carefully. You should keep the cream on overnight for eight to 14 hours, and then wash it off. Your close contacts (family and sex partners) also should be treated. Sheets, towels, and clothing should be washed in hot water and dried in a dryer at a high heat setting. Items that cannot be machine washed should be sealed in a plastic bag for at least 72 hours. Do not use pesticide sprays or powders because they are not helpful.
Can lice or scabies cause other problems?
Lice and scabies do not go away without treatment. The lice and mites do not cause infections, but skin can get infected from too much scratching.
What if the treatment doesn't work?
Sometimes treatments do not work even when used correctly. Talk to your doctor if the problem does not go away after two treatments.
Where can I get more information?
AAFP's Patient Education Resource
Centers for Disease Control and Prevention