Pinworms are common parasites that live in the intestine.
Copyright © Nucleus Medical Media, Inc.
A certain type of white worm causes the infection.
Pinworms can be seen. They look like a piece of thread and are about the size of a staple. They're spread by accidentally eating the eggs of the worm. They can be found on clothing, bedding, toys, or in the stool of someone who has them.
Pinworms are most active at night, 2-3 hours after bedtime. The female worm comes out through the anus and deposits eggs in the perineum area. This area is between the anus and genitals.
Pinworms are more common in children aged 5-14 years old. Your chances of pinworms are higher for:
Many people with pinworms don't have problems. In those that have them, they may cause:
Pinworms can be seen in stool or on the skin around the anus. If pinworms are suspected, but can't be seen, then you may have a tape test.
Place a piece of clear tape over the anus, press, and remove. Repeat it 2 to 3 times with new tape. Bring the tape samples to the doctor. They will check them for pinworms. Some labs supply special tape or pinworm paddles to use for this test.
The best time to do this test is 2 to 3 hours after bedtime. It can also be done before bathing in the early morning.
If needed, pinworms are treated with medicines. They're given in 2 or more doses, each separated by 2 weeks. To avoid reinfection, all members of the family should be treated.
To help lower your chances of a pinworm infection:
Healthy Children—American Academy of Pediatrics
National Institute of Allergy and Infectious Diseases
The College of Family Physicians of Canada
Enterobiasis. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T115562/Enterobiasis . Updated August 16, 2017. Accessed August 15, 2018.
Parasites—enterobiasis (also known as pinworm infection). Centers for Disease Control and Prevention website. Available at: https://www.cdc.gov/parasites/pinworm. Updated January 10, 2013. Accessed August 15, 2018.
Pinworm infestation. Merck Manual Professional Version website. Available at: https://www.merckmanuals.com/professional/infectious-diseases/nematodes-roundworms/pinworm-infestation. Updated February 2017. Accessed August 15, 2018.
Last reviewed May 2018 by
EBSCO Medical Review Board
Daus Mahnke, MD
Last Updated: 8/15/2018