What is the recommended treatment for enterobiasis (pinworm infection)?

Treatment for Pinworms (Enterobiasis)

The recommended first-line treatment for pinworm infection is either mebendazole 100 mg or albendazole 400 mg as a single oral dose, with a mandatory repeat dose in 2 weeks to eradicate newly hatched worms. 1, 2

Medication Options and Dosing

First-Line Agents (Equal Efficacy)

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

  • FDA-approved with 95% cure rate for pinworm 2
  • Can be chewed, swallowed, or crushed and mixed with food 2
  • Both adulticidal and ovicidal 3

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

  • Same standardized dose applies to all ages, including young children 1
  • Both adulticidal and ovicidal 3
  • Monitor for hepatotoxicity and leukopenia if treatment extends beyond 14 days 1

Alternative Agent

• Pyrantel pamoate 11 mg/kg (maximum 1 g): Single dose, repeated in 2 weeks 3
  • Preferred in pregnant women over mebendazole and albendazole 3
  • Only adulticidal (not ovicidal), which is why the 2-week repeat is critical 3

Critical Treatment Principles

The Two-Week Repeat Dose is Mandatory

• The repeat dose at 2 weeks is essential to kill worms that hatch from eggs that survived the first treatment 1
• Adult pinworms have a short lifespan, and the repeat dosing breaks the reinfection cycle 3

Treat All Household Members

• Treatment of all household members should be strongly considered, especially with multiple or repeated symptomatic infections 3, 4
• Sexual partners should also be included in treatment 4
• Reinfection is extremely common even with effective medication due to the ease of transmission 3

Diagnostic Confirmation (When Needed)

• Cellophane tape test: Apply sticky side of tape to perianal skin in the morning before bathing or bowel movement 1
  • Single test has ~50% sensitivity; three tests on different mornings increase sensitivity to ~90% 3
  • Pinworms and eggs are NOT usually passed in stool, so stool examination is not recommended 1, 3

Clinical Presentation to Recognize

• Most common symptom: Nocturnal perianal itching (pruritus ani) 1, 3
• Important caveat: 30-40% of infected patients are completely asymptomatic 1, 3
• Other symptoms: Weight loss, irritability, diarrhea, abdominal pain 1
• In girls: Vaginal discharge from female genital tract colonization 1

Management of Treatment Failure

• True treatment failure is rare 1
• Persistent symptoms after treatment usually indicate reinfection rather than medication resistance 1
• If symptoms persist 3 weeks after treatment, repeat the full treatment course (single dose plus 2-week repeat) 2, 3
• Consider whether household members were treated and whether hygiene measures are being followed 4

Essential Hygiene Measures to Prevent Reinfection

• 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, pajamas, and bed linens frequently in hot water 4

Special Populations

Children (All Ages Including Toddlers)

• Same adult doses apply: mebendazole 100 mg or albendazole 400 mg 1
• For children 12-24 months with suspected infection, expert consultation is recommended before treatment 5

Pregnant Women

• Pyrantel pamoate is preferred over mebendazole and albendazole 3

Common Pitfall to Avoid

The single biggest mistake is failing to give the repeat dose at 2 weeks and failing to treat household contacts. This leads to persistent reinfection cycles that families interpret as treatment failure, when in reality the medication worked but reinfection occurred immediately. 3, 4