What is the treatment for pinworm infection?

Treatment of Pinworm Infection

The first-line treatment for pinworm (Enterobius vermicularis) infection is a single dose of mebendazole 100 mg, which should be repeated in two weeks to eradicate newly hatched parasites. 1, 2

Medication Options

First-line treatments:

• Mebendazole: 100 mg as a single dose, repeated in 2 weeks 1, 2
  • Effective against both adult worms and eggs (adulticidal and ovicidal)
  • FDA-approved with 95% cure rate for pinworm 1

Alternative treatments:

• Albendazole: 400 mg as a single dose, repeated in 2 weeks 3, 2

  • Also adulticidal and ovicidal
  • Similar efficacy to mebendazole

• Pyrantel pamoate: 11 mg/kg (maximum 1 g) as a single dose, repeated in 2 weeks 3, 2

  • Only adulticidal (not ovicidal)
  • Preferred option for pregnant women 3, 2

Treatment Algorithm

1. Diagnosis confirmation:

   • Cellophane tape test (50% sensitivity for single test, 90% for three consecutive morning tests) 3, 2
   • Visual identification of worms in perianal area or stool is diagnostic 3
   • Note: Stool examination alone is not recommended as pinworms are not usually passed in stool 3

2. Initial treatment:

   • Administer mebendazole 100 mg as a single dose 1, 2
   • For pregnant women: Use pyrantel pamoate instead 3, 2
   • For children ≥2 years: Same adult dose (mebendazole 100 mg) 3
   • For children 12-24 months: Consult specialist before treatment 3
   • For children <12 months: Not recommended for routine deworming 3

3. Follow-up treatment:

   • Repeat the same dose in 2 weeks to kill newly hatched parasites 2
   • Treat all household members simultaneously to prevent reinfection 3, 2

4. For recurrent infections:

   • Consider prolonged treatment for up to 16 weeks using a "pulse scheme" 4
   • Reinforce hygiene measures (see prevention section)

Prevention of Reinfection

Crucial hygiene measures to prevent reinfection include:

• Frequent handwashing with soap, especially before eating and after using toilet 3
• Daily changing of underwear 3
• Keeping fingernails short and clean 3, 2
• Environmental cleaning:
  • Washing bed linens and night clothes in hot water 3
  • Vacuuming or damp mopping bedroom floors 3
  • Keeping toilet seats clean 3

Common Pitfalls and Caveats

1. Failure to treat all household members - This is a major cause of reinfection and treatment failure 3, 2

2. Inadequate follow-up - The second dose after 2 weeks is essential for complete eradication 2

3. Poor hygiene measures - Without addressing hygiene, reinfection is common due to the short life span of adult pinworms 2

4. Medication safety considerations:

   • For prolonged treatment courses (>14 days), monitor for hepatotoxicity (elevated liver enzymes in up to 16% of cases) and leukopenia (up to 10% of patients) 3, 5
   • In pregnant women, avoid mebendazole and albendazole if possible, with treatment preferably deferred until after the first trimester 3

5. Risk factors to address:

   • Playing on the floor (OR 2.5)
   • Nail biting (OR 2.1)
   • Failure to wash hands before meals (OR 1.7)
   • Living in non-apartment dwellings (OR 1.6) 3

By following this comprehensive treatment approach with appropriate medication, hygiene measures, and household-wide intervention, pinworm infections can be effectively managed with high cure rates.