Pinworm (Enterobiasis): Symptoms, Transmission, Treatment, and Prevention

Pinworms (Enterobius vermicularis) are tiny (½ inch), white, threadlike nematodes infecting the human colon. Most common helminthiasis in US children.

Symptoms

• Perianal itching (nocturnal) – female worms deposit eggs.
• Sleep disturbance, irritability.
• Abdominal pain, nausea (less common).
• Vaginal itching in girls (ectopic migration).
• Many asymptomatic.

Transmission

Fecal-oral: eggs on fingers → mouth. Eggs viable 2–3 weeks on surfaces (bedding, toys, toilet seats). Autoinfection common.

Diagnosis

• Scotch tape test: Apply clear tape to perianal skin morning (before bath), stick on slide; microscope for eggs. Repeat ×3 for sensitivity.
• Stool O&P less sensitive (eggs not in lumen).

Treatment

• Mebendazole 100 mg single dose (repeat in 2 weeks) – not available in US currently.
• Albendazole 400 mg single dose (repeat in 2 weeks) – preferred in US.
• Pyrantel pamoate 11 mg/kg (max 1 g) OTC; repeat in 2 weeks.
• Treat entire household simultaneously.

Hygiene Measures (During Treatment)

• Morning shower (remove eggs).
• Wash bedding, pajamas, towels in hot water; dry hot.
• Trim nails; discourage nail-biting, thumb-sucking.
• Vacuum, damp-mop floors.

Complications (Rare)

• Appendicitis (worms in appendix), salpingitis, UTI, weight loss.