Treatment of Pinworm Infection in Adults
For adult patients with pinworm infection, treat with a single oral dose of either albendazole 400 mg or mebendazole 100 mg, repeated in 2 weeks. 1, 2
First-Line Treatment Options
Both medications are equally effective and safe, with standardized dosing across all age groups including adults 1:
- Albendazole 400 mg: Single oral dose, repeat in 2 weeks 1
- Mebendazole 100 mg: Single oral dose, repeat in 2 weeks 1, 2
The FDA-approved mebendazole regimen specifically states the tablet may be chewed, swallowed, or crushed and mixed with food, with cure rates of approximately 95% for pinworm 2. Both albendazole and mebendazole are adulticidal and ovicidal, providing comprehensive treatment 3.
Why the Two-Dose Regimen is Critical
The repeat dose at 2 weeks is essential to eradicate any newly hatched worms from eggs that survived the initial treatment 1. This timing corresponds to the pinworm life cycle and prevents treatment failure 1.
Household and Contact Management
Treat all household members simultaneously, especially if there are multiple or repeated symptomatic infections, as reinfection is extremely common even with effective medication 3, 4. Sexual partners should also be included in treatment 4.
Clinical Presentation to Recognize
- Nocturnal perianal itching is the cardinal symptom and most common presentation 1, 3
- 30-40% of infected adults are completely asymptomatic 1, 3
- Other symptoms may include irritability, abdominal pain, diarrhea, and weight loss 1
- In women, vaginal discharge can occur from female genital tract colonization 1
Diagnostic Confirmation (When Needed)
The cellophane tape test applied to the perianal skin in the morning before bathing is the preferred diagnostic method, as pinworms and eggs are not usually passed in stool 1, 3. A single test has only 50% sensitivity, but three tests on different mornings increase sensitivity to approximately 90% 3.
Treatment Failure vs. Reinfection
Treatment failure is rare—persistent symptoms almost always indicate reinfection rather than medication resistance 1. The short life span of adult pinworms (approximately 6 weeks) combined with ease of transmission means recurrences are common despite effective treatment 3.
Essential Hygiene Measures
Medication alone is insufficient without concurrent hygiene interventions 3, 4:
- Frequent handwashing, especially after bowel movements and before meals 3
- Clip fingernails short 3
- Avoid finger-sucking, nail-biting, and scratching the anogenital area 3
- Daily morning bathing to remove eggs deposited overnight 4
- Change and wash underwear, bedding, and towels in hot water 4
Special Considerations for Recurrent Infections
For patients with persistent recurrent infections despite treatment and hygiene measures, prolonged "pulse scheme" treatment for up to 16 weeks may be necessary 4. This involves repeated dosing cycles to break the reinfection cycle 4.
Monitoring Requirements
No specific laboratory monitoring is required for the standard two-dose regimen 1. However, if albendazole treatment extends beyond 14 days (as in recurrent cases), monitor for hepatotoxicity and leukopenia 1.
Common Pitfall to Avoid
The most common error is treating only the symptomatic individual while ignoring household contacts, leading to rapid reinfection 3, 4. Always treat the entire household simultaneously for lasting success 4.