Pinworm infection is caused by the small worm called Enterobius vermicularis. It is the most common worm infection in the United States and it most commonly affects school-age children.

The pinworm's only reservoir is humans, and the worms are transmitted from person to person by ingesting eggs (oral-fecal route), or through contact with contaminated bedding, food, or other items.

Upon ingestion of eggs, larvae eventually hatch in the small intestine and worms then mature in the colon. Female worms then migrate to the anal area, especially at night, and deposit their eggs. This may lead to itching and sometimes infection of the involved area.

• intense itching around the anus
• irritability (usually due to itching and interruption of sleep at night)
• sleep disturbance (usually due to itching that occurs during the night when the adult worms migrate out through the anus to lay their eggs)
• decreased appetite and weight loss (this is uncommon but can occur in severe infections)
• vaginal irritation or discomfort in young girls (if an adult worm enters the vagina rather than the anus)
• excoriation, irritation or infection of the skin around the anus from constant scratching

The mainstay of treatment is antiparasitic medication such as pyrantel pamoate, mebendazole or albendazole. As more than one household member is likely to be infected, treatment of the entire household is often recommended. In addition, treatment is often repeated after 2 weeks.

General measures to control infestation are washing hands before meals and after use of the toilet, keeping fingernails short and clean, laundering all bed linen twice weekly, and cleaning toilet seats daily.

Avoid scratching the infected area (around the anus) as this contaminates the fingers and everything else that they subsequently touch. Keep hands and fingers away from the nose and mouth unless they are freshly washed. Carry out these measures while family members are treated with medication.

• salpingitis
• vaginitis
• reinfestation