Enterobiasis overview

Template:Pinworm Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

A pinworm is a small, thin, white roundworm (nematode) called Enterobius vermicularis that sometimes lives in the colon and rectum of humans. Pinworms are about the length of a staple. While an infected person sleeps, female pinworms leave the intestine through the anus and deposit their eggs on the surrounding skin.

The pinworm (Genus Enterobius) is a parasitic roundworm of the phylum Nematoda. Enterobiasis is the medical condition of being infected with pinworms (Enterobius vermicularis). It may be referred to, less precisely, as oxyuriasis, in reference to the family Oxyuridae, which contains the genus Enterobiasis.

Causes

The human pinworm Enterobius vermicularis and the more recently discovered Enterobius gregorii causes enterobiasis.

Epidemiology and Demographics

Pinworms are particularly common in children. The prevalence of pinworms is not associated with gender, race, social class, or culture. The pinworm has a worldwide distribution, and is the most common helminth (i.e., parasitic worm) infection in the United States and Western Europe.

Risk Factors

Children are at increased risk of having pinworm infection. Because it spreads from host to host through contamination, pinworms are common among people living in close contact, and tends to occur in all people within a household. Finger sucking has been shown to increase both incidence and relapse rates, and nail biting has been similarly associated.

Diagnosis

History and Symptoms

The symptoms may include painful itching around the anus, restless sleep, poor appetite, and failure to gain weight.

Laboratory Findings

Diagnosis is often made clinically by observing the female worm (or many worms) in the peri-anal region, but can also be made using the "scotch-tape" test, in which the sticky side of a strip of cellophane tape is pressed against the peri-anal skin, then examined under a microscope for pinworm eggs.

Treatment

Medical Therapy

Treatment is straightforward in uncomplicated cases, however, elimination of the parasite from a family group or institution often poses significant problems—either due to an incomplete cure or reinfection. The condition can be treated with mebendazole (Vermox), albendazole, piperazine (Antepar), or mostly commonly pyrantel pamoate (Combatrin, Povan). Taking a second dose of medication two weeks after the first will usually kill any pinworms that might have hatched in the meantime, before they are able to produce new eggs. More than one household member is likely to be infected, so the entire household is often treated.

Secondary Prevention

Great care should be taken to shower daily, and wash hands before every meal to avoid re-infection. All infected materials (pajamas, bedclothes, and underwear) should be washed with soap and hot water daily. Avoid scratching the infected area around the anus. This can contaminate your fingers and everything else that you touch afterwards. Keep your hands and fingers away from your nose and mouth unless they are freshly washed. Carry out these measures while family members are being treated for pinworms.

Videos

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Pinworms Found on Colonoscopy

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