Alternative Names

Enterobiasis; Oxyuriasis; Threadworm; Seatworm; Enterobius vermicularis; E vermicularis; Helminthic infection

Definition of Pinworms

Pinworms are small worms that infect the intestines.

Causes, incidence, and risk factors

Pinworms are the most common worm infection in the United States. They are most common in school-age children.

Signs and tests

Pinworms can be spotted in the anal area, especially at night when the worms lay their eggs there.


The main treatment is a single dose of either mebendazole or albendazole, which kill the pinworms (not the eggs).These are available over-the-counter and by prescription.

Expectations (prognosis)

Pinworm infection is fully treatable.


Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc. – 7/26/2010

Pinworm eggs
Pinworm, close-up of the head

ADAM Medical Encyclopedia

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