Pinworm Treatment
For pinworm (Enterobius vermicularis) infection, treat with a single oral dose of either albendazole 400 mg or mebendazole 100 mg, repeated in 2 weeks, and simultaneously treat all household contacts to prevent reinfection. 1, 2, 3
First-Line Treatment Options
You have two equally effective choices:
- Albendazole 400 mg orally as a single dose, repeated after 2 weeks 1, 2
- Mebendazole 100 mg orally as a single dose, repeated after 2 weeks 2, 3
Both medications can be chewed, swallowed whole, or crushed and mixed with food. 3 The FDA label confirms mebendazole achieves a 95% cure rate for pinworm with egg reduction approaching 100%. 3 The same dose applies to both children and adults—there is no weight-based adjustment needed for pinworm treatment. 2, 3
Critical Treatment Principle: Treat All Household Contacts
The American College of Gastroenterology recommends treating all household contacts simultaneously, even if asymptomatic, due to the highly contagious nature of pinworm infection. 1 This is essential because:
- Reinfection rates are extremely high without simultaneous household treatment 4
- 30-40% of infected individuals are completely asymptomatic but still transmit infection 2, 4
- Transmission occurs not only through fecal-oral route but also through inhalation of airborne eggs 5
Why the Two-Week Repeat Dose Matters
The repeat dose at 2 weeks is necessary to eradicate newly hatched worms from eggs that survived the initial treatment, as both medications are adulticidal and ovicidal but eggs may persist in the environment. 2, 4 This timing corresponds to the prepatent period before new worms reach reproductive maturity.
When Treatment Appears to Fail
If symptoms persist after completing the two-dose regimen:
- This usually indicates reinfection rather than treatment resistance, which is extremely rare for pinworm 2
- Consider whether all household contacts were treated simultaneously 4
- Reassess hygiene measures (see below) 4
- A third treatment course may be warranted if reinfection is confirmed 3
Essential Hygiene Measures to Prevent Reinfection
Medication alone is insufficient without these concurrent measures:
- Hand hygiene with soap after bowel movements and before meals 1
- Clip fingernails short to reduce egg accumulation under nails 4
- Avoid nail-biting, finger-sucking, and scratching the perianal area 4
- Morning bathing to remove eggs deposited overnight 4
- Daily changing and washing of underwear and bedding in hot water during treatment period 4
Special Clinical Considerations
Diagnostic Approach
- The cellophane tape test (applied to perianal skin first thing in the morning before bathing) is the diagnostic method of choice 2
- A single test has only 50% sensitivity, but three tests on consecutive mornings increase sensitivity to 90% 4
- Stool examination is not recommended as pinworms and eggs are rarely passed in stool 2, 4
Atypical Presentations
- In girls, watch for vaginal discharge from female genital tract colonization, which may require extended treatment 2, 5
- Ectopic vaginal infection can serve as a reservoir for recurrent infection even with complete gastrointestinal treatment 6
Pregnancy
- For pregnant women, pyrantel pamoate is preferred over albendazole or mebendazole due to safety profile 4
Monitoring for Extended Treatment
- If treatment extends beyond 14 days (rare for pinworm but relevant for complicated cases), monitor for hepatotoxicity and leukopenia 2, 7
No Special Preparation Required
Unlike historical treatments, no fasting, purging, or other preparatory procedures are necessary before taking these medications. 3