(Pinworm Infection in Children and Adults, Enterobiasis)

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Pinworms facts

  • Pinworm infections are caused by worm-like parasites that infect humans' intestines and rectal/anal areas.
  • Young children and their household members are at risk for pinworm infections.
  • Pinworms are visible. They range in size from 2-13 mm, are white, and resemble a worm but the pinworm eggs are small, transparent and can be seen only with a microscope.
  • Pinworm infections are spread person-to-person by ingesting pinworm eggs that have contaminated fingers, bedding, clothing or other items.
  • The symptoms of pinworm infection are discomfort and itching in the anal/rectal 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.

What is pinworm infection in humans?

Pinworm infection is an infection of the large intestine and anal area by a small, white parasite that resembles a "worm." The medical name for the parasite is Enterobius vermicularis, but it is commonly termed a pinworm in both the lay and medical literature. These parasites are also termed seatworms or threadworms, and the infections is medically termed enterobiasis or helminthiasis. Pinworms and other parasitic worms (which, as a group, are termed helminths) feed off of the host animal by adsorbing nutrients from the host animal. Pinworm infections are the most common helminth infection that occurs in the US.

Medically Reviewed by a Doctor on 2/6/2015

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What Do Pinworms Look Like?

Pinworms are white, can be seen with the naked eye, and are about the length of a staple. At night, adult pinworms can sometimes be seen directly on the person's pajamas or around the anal area. The best time to look for pinworms is at night when the person wakes up due to itching in the anal/rectal. This sensation is likely caused by migrating female worms depositing eggs and irritating the skin.