Pinworms

September 14, 2005
Robert P. Blereau, MD
Robert P. Blereau, MD

Enterobiasis-an infection by pinworms-is caused by the nematode Enterobius vermicularis. Treatment is a single dose of oral albendazole, mebendazole, or pyrantel pamoate.

For 2 days, a 3-year-old girl had been incessantly scratching at her nostrils and at her perianal area. The grandmother had seen pinworms on the child's perianal area but not on the nostrils.

Robert P. Blereau, MD of Morgan City, La, writes that enterobiasis-an infection by pinworms-is caused by the nematode Enterobius vermicularis. The disease occurs in persons of all ages worldwide; however, children are most often affected, especially those who live in a congested family or institutional environment. The parasitic threadworms are transmitted by ingestion of embryonated eggs, which hatch in the stomach and travel to the colon, where they mature. Adult worms cause nocturnal perianal pruritus and restlessness as they migrate externally.

Diagnosis is made by visualizing the adult worm. To obtain eggs for microscopic examination, press adhesive tape or a sticky slide to the perianal area at night or in the early morning.

Treatment for children and adults is a single dose of either oral albendazole, 400 mg; oral mebendazole, 100 mg; or oral pyrantel pamoate, 11 mg/kg (maximum dose, 1g); this regimen is repeated 2 weeks later. All members of the household need to be treated.

This patient and all residents of her home were given a single chewable tablet of mebendazole, 100 mg, followed by a second tablet 2 weeks later. To minimize possible reinfection, the family was encouraged to follow good personal hygiene, laundry, and housecleaning practices.