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Children's Health

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Pinworms - Topic Overview

What are pinworms?

Pinworms are a type of parasite that lives in the digestive system camera.gif of humans. They are common throughout the world.

Adult pinworms are about 0.5 in. (12.7 mm) long and look like little white threads. Pinworm eggs are so tiny, you'd need a microscope to see them.

What causes pinworm infection?

Most people get infected by accidentally swallowing pinworm eggs. Anyone can get pinworms, but they are most common in school-aged children. They are usually spread like this:

  • A child swallows pinworm eggs, and they travel to the child's intestines. In about a month, the eggs hatch into worms. At night the female worms crawl out the rectum and lay eggs around the child's anus.
  • When the worms lay eggs, it can cause itching. If the child scratches, the eggs can cling to the child's fingers and get stuck under the fingernails.
  • The eggs then stick to things the child touches, such as clothing, dishes, toys, and furniture. The eggs can live 2 to 3 weeks outside the body.
  • When you touch something the child has touched, the eggs get on your hands. Then if you touch food or your mouth, you can swallow the eggs. This starts the cycle over again.

Pinworms spread easily in homes, day care centers, schools, and other places where groups of people spend time together. So if one person in your family has pinworms, others probably do too.

It's possible to get pinworms by inhaling airborne eggs, but this is rare. It's also rare to get pinworms from a swimming pool.

Pinworms are spread from person to person. Pets don't get pinworms and can't spread them to humans.

What are the symptoms?

Many people with pinworms don't have symptoms and don't know that they're infected. When symptoms occur, the most common ones are:

  • Itching around the anus.
  • Restless sleep, because itching is often worse at night.

Pinworms can be annoying. But they don't carry disease, and they rarely cause serious health problems. Sometimes people get a skin infection from scratching.

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