Treatment of Pinworm (Enterobius vermicularis) Infection
Albendazole 400 mg as a single oral dose, repeated exactly 2 weeks later, is the recommended first-line treatment for pinworm infection in adults and children older than 24 months. 1
First-Line Treatment Regimen
Albendazole 400 mg orally as a single dose, with a mandatory second dose at exactly 2 weeks is required because eggs present at the time of the first dose hatch into new adult worms within 2–4 weeks; the second dose eliminates these newly emerged worms and achieves complete eradication. 1
Mebendazole 100 mg as a single oral dose, repeated in 2 weeks is an equally effective alternative to albendazole, with both drugs being adulticidal and ovicidal. 2, 3
Pyrantel pamoate 11 mg/kg (maximum 1 gram) as a single oral dose, repeated in 2 weeks is another alternative, though it is only adulticidal (not ovicidal) and therefore theoretically less effective than albendazole or mebendazole. 2, 4
Pediatric Dosing Considerations
Children older than 24 months receive the same 400 mg albendazole dose as adults, simplifying dosing across this age group. 1
Children 12–24 months may receive the 400 mg dose, but treatment should be undertaken only after expert consultation to ensure safety and appropriateness. 1
Children under 2 years or weighing less than 25 lbs should not receive pyrantel pamoate unless directed by a physician. 4
Administration Requirements
Albendazole should always be taken with food, preferably a fatty meal, to ensure optimal absorption. 1
Pyrantel pamoate can be taken any time of day, with or without meals, and may be taken alone or with milk or fruit juice; no laxative is necessary. 4
Mebendazole tablets may be chewed, swallowed, or crushed and mixed with food, and no special procedures such as fasting or purging are required. 3
Household and Contact Management
When one individual in a household has pinworms, the entire household should be treated simultaneously unless otherwise advised, because reinfection is extremely common even when effective medication is given. 2, 4
Treatment of all household members, including sexual partners, is a prerequisite to lasting success and prevention of recurrence and autoinfection. 5
Environmental Hygiene Measures
On each day an albendazole dose is administered, thorough vacuuming of bedroom floors and furniture is recommended to remove contaminating pinworm eggs from surfaces. 1
Cleaning bathroom fixtures—especially toilet seats and door handles—on treatment days helps reduce environmental reservoirs of viable eggs and prevents reinfection. 1
Good personal hygiene, including frequent handwashing (especially after bowel movements and before meals), clipping of fingernails, and avoidance of finger-sucking, nail-biting, and scratching in the anogenital area, are essential preventive measures. 2
Special Considerations in Pregnancy
For pregnant women, pyrantel pamoate is the preferred agent over mebendazole and albendazole, given its safety profile. 2
Albendazole should be used in pregnancy only when the therapeutic benefit clearly outweighs potential fetal risk. 1
Clinical Presentation
The most frequent symptom of pinworm infection is nocturnal perianal itching (pruritus ani). 1
Additional possible manifestations include weight loss, irritability, diarrhea, abdominal pain, and vulvovaginitis in female patients due to colonization of the female genital tract. 1, 6
Diagnostic Approach
The diagnosis of E. vermicularis infection is best established by the perianal adhesive tape test (cellophane tape test), which is preferred to fecal concentrate examination. 7
The sensitivity of one single tape test is around 50%; however, sensitivity increases to approximately 90% with tests performed on three different mornings. 2
As pinworms and eggs are not usually passed in the stool, examination of the stool is not recommended. 2
Management of Recurrent Infections
For recurrent infections, prolonged treatment for up to 16 weeks using a "pulse scheme" is recommended, though the specific dosing schedule should be determined in consultation with an expert. 5
Recurrences are likely due to repeated cycles of reinfection (particularly autoinfection) because of the short life span of adult pinworms, emphasizing the importance of simultaneous household treatment and rigorous hygiene measures. 2
Common Pitfalls to Avoid
Failure to treat all household members simultaneously is the most common cause of treatment failure and recurrent infection. 2, 5
Omitting the second dose at 2 weeks allows newly hatched larvae to mature into egg-laying adults, perpetuating the infection cycle. 1
Inadequate environmental decontamination on treatment days leaves viable eggs on surfaces, leading to rapid reinfection even after successful pharmacologic treatment. 1