Pinworm Infestation (Enterobiasis) - Treatment

First-Line Drugs

Three drugs are effective. All require a two-dose strategy (initial dose + repeat at 2 weeks):

Drug	Dose	Notes
Pyrantel pamoate	11 mg/kg (max 1 g) orally, single dose	OTC in the US; most affordable
Mebendazole	100 mg orally, single dose	Prescription in US; highly effective
Albendazole	400 mg orally, single dose	Prescription; not FDA-approved for pinworms but widely used

The second dose at 2 weeks is essential because anthelmintics act on adult worms but not on eggs - the repeat dose kills newly hatched adults before they can reproduce.
Mebendazole and albendazole are significantly more costly than pyrantel in the US.

Treat the Entire Household

Because reinfection is extremely common (eggs survive in the environment up to 2 weeks), all household members should be treated simultaneously, regardless of symptoms. This is the single most important step to break the transmission cycle.

Special Populations

Children under 2 years: Use of all three drugs is off-label and limited in evidence - weigh risks vs. benefits carefully before treating.
Pregnant women: Mebendazole and albendazole are potentially teratogenic. Because E. vermicularis has very low pathogenicity, treatment is typically deferred until after delivery.
Ivermectin: Has been evaluated and is partially effective, but safety in children under 15 kg and in pregnant women is not established.

Refractory / Recurrent Cases

"Pulse" treatment - a single dose of mebendazole every 14 days for 16 weeks - has been used successfully in refractory cases with multiple recurrences.

Hygiene and Environmental Control Measures

Drug treatment alone is insufficient without concurrent hygiene measures:

Morning shower/bath to remove eggs deposited overnight
Frequent hand washing, especially before meals and after toileting
Clip fingernails short (eggs accumulate under nails)
Launder bed linens and underwear of infected individuals promptly; do not shake them (scatters eggs into the air)
Eggs can remain infective in indoor environments for up to 2 weeks

Diagnosis Reminder

The cellophane (Scotch) tape test applied to the perianal region first thing in the morning (before bathing or defecation) is the gold standard. Three samples on different days raises sensitivity to ~90% (vs. ~50% for a single test). Stool examination is not useful, as eggs are rarely found in stool.

Complications Requiring Attention

Vulvovaginitis / salpingitis / pelvic peritonitis: Can result from aberrant worm migration - treat the underlying infestation.
Appendiceal involvement: Pinworms are occasionally found in the appendix lumen; treat with mebendazole postoperatively if discovered at laparoscopy.
Bacterial superinfection: Secondary to scratching and excoriation - treat as needed.

Sources: Red Book 2021 (AAP Committee on Infectious Diseases), p. 916-917; Sleisenger and Fordtran's Gastrointestinal and Liver Disease, p. 2273

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