Pinworms (Pinworm Infection in Children and Adults, Enterobiasis)

  • Medical Author:
    Charles Patrick Davis, MD, PhD

    Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

  • Medical Editor: Melissa Conrad Stöppler, MD
    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

  • Medical Editor: Jay W. Marks, MD
    Jay W. Marks, MD

    Jay W. Marks, MD

    Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

Pinworms Pictures Slideshow: Symptoms, Treatments, and Medication

Who is at risk for getting pinworms?

Pinworm is the most common worm infection in the United States, and the majority of pinworm infections worldwide occur in temperate climates.

Pinworms in children

School-age children have the highest rates of pinworm infection. They are followed by preschoolers. Institutional settings including day care facilities often harbor cases of pinworm infection. Sometimes, nearly half of the children may be infected.

Pinworms in adults

Pinworm infection often occurs in more than one family member. Adults are less likely to have pinworm infection, except for mothers of infected children. However, adult sexual partners can transfer the eggs to each other.

What do pinworms look like (pinworm pictures)?

The pinworms are white, can be seen with the naked eye (no magnification) and are about the length of a staple (about 8-13 mm for female and 2-5mm for male worms). The eggs that are laid by the female worms are not visible as they are about 55 micrometers in diameter and are translucent (see Figure 1).

The male and female worms live for the most part within the rectum of humans but have a life cycle in humans that involves rectal/oral transmission (see Figure 2).

While an infected person is asleep, female pinworms leave the intestines through the anus and deposit eggs on the skin around the anus. This causes itching and irritation of the surrounding area; children especially will scratch the rectal/anal area, get eggs on their fingers or underneath their fingernails and transport the infective eggs to bedding, toys, other humans, or back to themselves. The eggs hatch into larval forms in the small intestines and then progress to the large intestine where they mature, mate, and progress to the rectal/anal area where females deposit about 10 to 15 thousand eggs.

Figure 1, picture of pinworm and pinworm eggs (magnified); (image courtesy of CDC.gov)

Picture of pinworms
Picture of pinworms
Picture ofthe life cycle of a pinworm
Picture of the life cycle of a pinworm
Medically Reviewed by a Doctor on 2/6/2015

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