Pinworm Infection (Enterobiasis): Complete Guide to Symptoms, Diagnosis, Treatment, and Prevention

Enterobius vermicularis (pinworm) is a ½-inch white nematode infecting the human colon. Most common helminth in US children.

Symptoms

• Intense perianal itching (nocturnal) – female lays eggs.
• Sleep disruption, irritability, daytime fatigue.
• Abdominal discomfort, nausea (less common).
• Vulvovaginitis in girls (ectopic migration).
• Often asymptomatic.

Transmission

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

Diagnosis

• Scotch tape test: Morning (pre-bath) perianal tape → microscope for eggs. Repeat ×3 for 90% sensitivity.
• Visualization of worms on perianal skin at night (flashlight).
• Stool O&P insensitive (eggs not in lumen).

Treatment

• Albendazole 400 mg single dose (repeat 2 weeks) – preferred in US.
• Pyrantel pamoate 11 mg/kg (max 1 g) OTC single dose (repeat 2 weeks).
• Mebendazole 100 mg single dose (repeat 2 weeks) – unavailable in US currently.
• Treat entire household simultaneously regardless of symptoms.

Hygiene During Treatment

• Morning shower (wash eggs away).
• Hot wash/dry bedding, pajamas, towels daily ×2 weeks.
• Trim nails; no nail-biting.
• Vacuum, damp-mop floors.
• Change underwear daily.

Complications (Rare)

• Appendicitis (worms in appendix).
• Salpingitis, peritoneal granulomas.
• Urinary tract infection.
• Weight loss, malnutrition (heavy burden).

Prevention

• Hand hygiene (after toilet, before meals).
• Short nails.
• Avoid sharing towels/bedding.
• Treat promptly to reduce environmental contamination.