Pinworms - Topic Overview
What are pinworms?
Pinworms are a type of
parasite that lives in the
digestive system 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.
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.
How are pinworms diagnosed?
To find out if you have pinworms, your doctor will ask about your past health and check the skin around your
The doctor may ask you to do a transparent tape test at home. To do the test, you press a piece of clear, sticky tape on the skin around your anus in the morning before you get up. The doctor will put the tape under a microscope
to look for pinworm eggs. You might need to repeat this test a few times.