Pinworm infection (enterobiasis)
Pinworm infection (enterobiasis) is caused by the nematode Enterobius vermicularis and is the most common helminthic infection in children, presenting with perianal pruritus that is worse at night. Diagnosis is made by the cellophane tape test performed on first waking, and treatment is a single oral dose of albendazole, mebendazole, or pyrantel pamoate given to the patient and all household members, repeated after two weeks to break the autoinfection cycle.
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What this article covers
- Overview
Pinworm infection (enterobiasis) is caused by Enterobius vermicularis, a small white intestinal nematode and the most common helminthic infection in the United States and other temperate climates.
- Epidemiology
Enterobiasis is the most common intestinal helminthic infection in industrialized countries, with the highest prevalence in school-aged and preschool-aged children.
- Risk factors
Young school age (5 to 10 years), the population with the highest exposure to communal and close-contact settings.
- Pathophysiology
Infection begins with ingestion of embryonated Enterobius vermicularis eggs, transmitted by the fecal-oral route directly from another person's perianal skin, from contaminated fomites (bedding…
- Clinical features
Perianal pruritus, characteristically worse at night, is the defining symptom and is present in essentially all symptomatic infections; this pattern reflects the nocturnal migration of gravid female worms to lay eggs on the perianal skin.
- Differential diagnosis
Candidal or contact dermatitis of the perianal skin: perianal erythema and itching without nocturnal predominance and without visible worms or positive tape test.
- Diagnosis
Enterobiasis is confirmed by direct visualization of the worm or its eggs; there is no serologic test, and routine stool ova-and-parasite examination is insensitive because the worms lay eggs on the…
- Management
First, treat the infected patient and every household member simultaneously, regardless of whether each individual has symptoms, because asymptomatic carriers perpetuate household transmission.
- Complications
Secondary bacterial skin infection of excoriated perianal skin from repeated scratching.
- Prognosis
Enterobiasis is a benign, self-limited infection with an excellent prognosis once treated; it does not cause the tissue invasion or systemic illness associated with other helminths.
- Prevention
Treat all household members at the same time as the index case, with the repeat dose given 2 weeks later, including asymptomatic contacts, since even one untreated person can reseed the household.
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