The infection is caused by a specific type of small, thin, white roundworm. They look like a piece of thread and are about the size of a staple.
The infection spreads when a person eats the eggs of the worm. This can happen from contact with the stool of an infected person. It can also happen by touching clothing, bedding, food, or other items that contain them.
This problem is more common in children under 14 years of age. Other things that may raise the risk are:
- Contact with a person who has them—usually another child or family member
- Contact with clothing, bedding, or objects that have pinworms on them
- Regular exposure to schools, daycare centers, and other places where pinworms are found
The doctor will ask about your symptoms and health history. A physical exam will be done. The doctor may see the pinworms in the area between the anus and genitals. This is enough to make the diagnosis.
Other people may need a tape test to look for pinworm eggs. A person may be asked to do the test at night when the pinworms are most active. A piece of clear tape is placed over the anus and removed. Any eggs will appear on the tape.
The doctor may also look for eggs by taking samples from under a person's fingernails.
This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.
Edits to original content made by Denver Health.
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a (Enterobiasis, Roundworm)
Healthy Children—American Academy of Pediatrics https://www.healthychildren.org
National Institute of Allergy and Infectious Diseases https://www.niaid.nih.gov
The College of Family Physicians of Canada https://www.cfpc.ca
Health Canada https://www.canada.ca
Enterobiasis. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/enterobiasis-pinworm-infection. Accessed November 25, 2020.
Parasites—enterobiasis (also known as pinworm infection). Centers for Disease Control and Prevention website. Available at: https://www.cdc.gov/parasites/pinworm. Accessed November 25, 2020.
Pinworm infestation. Merck Manual Professional Version website. Available at: https://www.merckmanuals.com/professional/infectious-diseases/nematodes-roundworms/pinworm-infestation. Accessed November 25, 2020.
Truscott J, Abebe A, et al. Recognizing common parasitic infestations. JAAPA. 2017 May;30(5):1-6.