What is the recommended treatment for pinworms (enterobiasis)?

Treatment for Pinworms (Enterobiasis)

The recommended first-line treatment for pinworms is either mebendazole 100 mg or albendazole 400 mg as a single oral dose, repeated in 2 weeks, with both medications showing equivalent efficacy and safety across all age groups. 1, 2

Medication Options

First-Line Agents (Equal Efficacy)

• Mebendazole 100 mg: Single oral dose, repeated in 2 weeks 1, 2

  • Cure rate of 95% for pinworm infection 2
  • Both adulticidal and ovicidal (kills adult worms and eggs) 3
  • Standardized dose applies to all ages, including children as young as 2 years 1

• Albendazole 400 mg: Single oral dose, repeated in 2 weeks 1

  • Equally effective as mebendazole with standardized dosing across all age groups 1
  • Both adulticidal and ovicidal 3
  • If treatment extends beyond 14 days (rare for pinworms), monitor for hepatotoxicity and leukopenia 1

Alternative Agent

• Pyrantel pamoate: 11 mg/kg (maximum 1 gram) as a single oral dose, repeated in 2 weeks 4, 3
  • Only adulticidal (does not kill eggs), making it slightly less effective than benzimidazoles 3
  • Preferred in pregnancy over mebendazole and albendazole 3
  • Can be taken with or without food, no laxative needed 4

Critical Treatment Considerations

The Two-Week Repeat Dose

• The second dose at 2 weeks is essential to eradicate newly hatched worms from eggs that survived the first treatment 1
• This timing corresponds to the pinworm life cycle and prevents treatment failure 1

Household Treatment Strategy

• Treat all household members simultaneously, especially when multiple or repeated symptomatic infections occur 3, 5
• Reinfection is extremely common even with effective medication due to the ease of transmission 3, 5
• Consider treating sexual partners as well for lasting success 5

Clinical Presentation to Recognize

Common Symptoms

• Nocturnal perianal itching is the hallmark symptom 1
• 30-40% of infected patients are completely asymptomatic 1, 3
• Other manifestations: weight loss, irritability, diarrhea, abdominal pain 1
• In girls: vaginal discharge from female genital tract colonization 1

Diagnostic Approach

• Cellophane tape test is the diagnostic method of choice 1
  • Apply sticky side of tape to perianal skin in the morning before bathing 1
  • Single test has ~50% sensitivity; three tests on different mornings increase sensitivity to ~90% 3
• Stool examination is NOT recommended as pinworms and eggs are rarely passed in stool 1, 3

Managing Persistent Symptoms

When Treatment Appears to Fail

• True treatment failure is rare—persistent symptoms usually indicate reinfection rather than medication resistance 1
• Recurrences are common due to repeated cycles of autoinfection and the short life span of adult worms 3
• For recurrent infections, consider prolonged "pulse scheme" treatment for up to 16 weeks 5

Essential Hygiene Measures

Prevention of Reinfection

• Frequent handwashing, especially after bowel movements and before meals 3
• Clip fingernails short to reduce egg accumulation 3
• Avoid finger-sucking, nail-biting, and scratching the anogenital area 3
• Daily morning bathing to remove eggs deposited overnight 3
• Change and wash underwear, bedding, and towels in hot water 5

Common Pitfalls to Avoid

• Failing to treat household members: This is the most common reason for apparent treatment failure 3, 5
• Omitting the second dose at 2 weeks: Single-dose treatment alone has higher failure rates 1
• Examining stool samples: This wastes time and resources as pinworms are not detected in stool 1, 3
• Assuming medication resistance: Reinfection, not resistance, explains most persistent cases 1