Pinworm Treatment
For suspected pinworm infection, treat with a single dose of either mebendazole 100 mg or albendazole 400 mg orally, repeated in 2 weeks, and treat all household members simultaneously to prevent reinfection. 1, 2
First-Line Treatment Options
Both medications are equally effective and safe across all age groups:
- Mebendazole 100 mg as a single oral dose, repeated in 2 weeks 1, 2
- Albendazole 400 mg as a single oral dose, repeated in 2 weeks 1, 3
The tablet may be chewed, swallowed, or crushed and mixed with food. 2 No fasting or purging is required before treatment. 2
Mebendazole achieves a 95% cure rate for pinworm infection. 2 Both mebendazole and albendazole are adulticidal (kill adult worms) and ovicidal (kill eggs), making them superior to alternatives. 4
Critical Treatment Principles
Treat all household members simultaneously, even if asymptomatic:
- 30-40% of infected individuals have no symptoms 4, 5
- Reinfection is extremely common without household treatment 4, 5
- Sexual partners should also be treated 5
The two-dose regimen (initial dose plus repeat in 2 weeks) is essential:
- The second dose eradicates newly hatched worms from eggs that survived the first treatment 1
- Adult pinworms have a short lifespan, but eggs can persist in the environment 4
Age-Specific Dosing
The same standardized dose applies to all ages:
- Children ≥2 years: Mebendazole 100 mg or Albendazole 400 mg 1
- Children 12-24 months: Expert consultation recommended before treatment 6
- Adults: Same dosing as children 1, 2
Clinical Presentation to Recognize
Most common symptom is nocturnal perianal itching (pruritus ani), occurring when female worms migrate to deposit eggs. 1, 4
Other presentations include:
- Asymptomatic (30-40% of cases) 4
- Irritability, restlessness, insomnia from itching 4, 7
- Weight loss, abdominal pain, diarrhea 1
- Vaginal discharge in girls (from female genital tract colonization) 1, 8
- Skin irritation or secondary bacterial infection from scratching 7
Diagnostic Approach
Cellophane tape test is the preferred diagnostic method:
- Apply sticky side of tape to perianal skin in the morning before bathing or bowel movement 1, 3
- Single test has ~50% sensitivity; three tests on consecutive mornings achieve ~90% sensitivity 4
- Pinworms and eggs are NOT usually passed in stool, so stool examination is not recommended 1, 4
Visual identification of worms:
- Adult worms may be visible in perianal area or stool 4
- Pathological examination of the worm provides definitive diagnosis 4
Treatment Failure and Reinfection
Persistent symptoms after treatment almost always indicate reinfection, not medication resistance:
- Treatment failure with these medications is rare 1
- Recurrence is common due to autoinfection and environmental contamination 4, 5
- If symptoms persist 3 weeks after treatment, repeat the full two-dose course 2, 4
Essential Hygiene Measures
These measures must accompany medication to prevent reinfection:
- Frequent handwashing, especially after bowel movements and before meals 4
- Clip fingernails short 4
- Avoid finger-sucking, nail-biting, and scratching the anogenital area 4
- Daily morning bathing to remove eggs deposited overnight 5
- Change and wash underwear, bedding, and towels in hot water 5
Special Populations
Pregnant women: Pyrantel pamoate is preferred over mebendazole or albendazole due to safety profile. 4
Prolonged treatment (>14 days): Monitor for hepatotoxicity and leukopenia if extended treatment courses are needed for recurrent infections. 1
Common Pitfalls to Avoid
- Failing to treat household members leads to rapid reinfection 4, 5
- Omitting the second dose at 2 weeks allows newly hatched worms to mature 1
- Relying on stool examination will miss most cases since eggs are deposited perianally, not in stool 1, 4
- Assuming treatment failure when symptoms recur—this is usually reinfection requiring repeat treatment and stricter hygiene 1, 4