pinworm

Pinworm, or Enterobius vermicularis, is a small white parasitic nematode and the most common intestinal worm infection in temperate climates. It primarily affects children but can occur at any age. People harboring pinworms may be asymptomatic.

Transmission and life cycle

Pinworm eggs are laid around the anus by female worms, usually at night. The eggs are immediately infective when ingested or transferred to the mouth via contaminated hands or objects. Eggs can survive on surfaces, bedding, and clothing for several days to weeks, facilitating fomite transmission and autoinfection through scratching.

Symptoms

The hallmark symptom is perianal itching, especially at night. This can lead to sleep disturbance and irritability. Some people have mild abdominal discomfort or nausea. Complications are rare but can include secondary bacterial infections from scratching.

Diagnosis

Diagnosis is commonly made with the tape test: a piece of clear adhesive applied to the perianal area in the morning before bathing, then examined under a microscope for eggs. Stool tests are less sensitive. Visualization of worms during the night is possible but not required.

Treatment and prevention

Treatment usually involves anthelmintic medications such as mebendazole, albendazole, or pyrantel pamoate, given as a dose now and a second dose after about two weeks to reduce reinfection. All household members and close contacts are often treated, even if asymptomatic. Wash and heat-dry the person’s bedding, towels, and clothing; vacuum and wipe surfaces; maintain short nails and good hand hygiene; encourage morning baths to remove eggs from the perianal area. With proper treatment and hygiene, pinworm infections resolve quickly.