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Home > Health Library > 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.
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:
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.
Many people with pinworms don't have symptoms and don't know that they're infected. When symptoms occur, the most common ones are:
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.
To find out if you have pinworms, your doctor will ask about your past health and check the skin around your anus.
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.
You can treat pinworms with over-the-counter or prescription medicine that kills the worms. Treatment can help keep you from getting infected again and from spreading the infection to other people.
You will probably need two doses, 2 weeks apart. That's because the medicine kills the worms but not the eggs. The second dose will kill any worms that hatch after the first treatment.
Pinworm medicine may not be safe for children younger than 2 and women who are pregnant or breastfeeding. So to reduce their risk of infection, a doctor may recommend that all other household members be treated with medicine.
Call your doctor if:
Pinworms spread easily and often come back. To reduce your chances of spreading the infection or getting infected again:
If anyone in your household gets pinworms again, the whole family may need to take medicine.
Current as of: August 22, 2019
Author: Healthwise StaffMedical Review: John Pope, MD, MPH - PediatricsKathleen Romito, MD - Family Medicine
Current as of: August 22, 2019
Author: Healthwise Staff
Medical Review:John Pope, MD, MPH - Pediatrics & Kathleen Romito, MD - Family Medicine
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