Enterobius vermicularis: Overview and Treatment
Albendazole 400 mg as a single dose is the recommended first-line treatment for Enterobius vermicularis (pinworm) infection. 1
What is Enterobius vermicularis?
Enterobius vermicularis, commonly known as pinworm or threadworm, is an intestinal nematode with the following characteristics:
- It has a worldwide distribution, particularly affecting children 2
- The prepatent period (time from infection to egg production) is 2-6 weeks 1
- Transmission occurs via the fecal-oral route, including self-infection, oral-anal contact, or from contaminated surfaces and fomites 1
- It primarily affects the terminal ileum and large intestine 3
Clinical Presentation
Enterobius vermicularis infection often presents with:
- Pruritus ani (intense anal itching), which is the most common symptom 1
- Frequently asymptomatic in many cases 1
- Possible vulvovaginitis in females due to worm migration into the genital tract 1
- Sometimes weight loss, irritability, diarrhea, and abdominal pain 1
- Occasionally colitis with eosinophilia 1
In rare cases, extraintestinal migration can occur, potentially leading to:
- Involvement of other organs such as kidneys or lungs (extremely rare) 3
- Inflammation of Meckel's diverticulum (extremely rare) 4
Diagnosis
The diagnosis of Enterobius vermicularis is made through:
- The "sellotape test" (adhesive tape test) - applying adhesive tape to the perianal region in the morning before defecation or bathing to collect eggs 1
- Concentrated stool microscopy or fecal PCR, though eggs may be absent in stool samples 1
- Visualization of adult worms in the perianal region, particularly at night 1
Treatment Options
First-line Treatment:
Albendazole 400 mg as a single oral dose 1
Alternative treatments include:
- Mebendazole 100 mg as a single oral dose 5
- Pyrantel pamoate (dosage based on weight)
Treatment Considerations:
- Treatment should be repeated after 2 weeks to address reinfection from eggs that may have hatched after initial treatment 1
- All household members should be treated simultaneously to prevent reinfection 6
- Environmental measures are important: washing bedding, underwear, and nightclothes in hot water; regular cleaning of living spaces 2
- Hand hygiene is crucial - washing hands after toilet use and before eating significantly reduces risk of infection 2
Risk Factors and Prevention
The following factors increase the risk of Enterobius vermicularis infection:
- Living in crowded conditions with ≥9 family members (OR 3.63) 2
- Poor hand hygiene, particularly not washing hands after toilet use (OR 2.4) 2
- Living in rural areas (OR 2.25) 2
- Young age, particularly preschool and school-aged children 2
Prevention strategies include:
- Regular hand washing, especially after using the toilet and before eating 2
- Keeping fingernails short and clean 2
- Avoiding nail-biting and finger-sucking behaviors 2
- Regular changing and washing of underwear, bedding, and pajamas 2
- Treatment of all household contacts simultaneously 6
Special Considerations
- Co-infection with other parasites, such as Dientamoeba fragilis, may require simultaneous treatment of both parasites 6
- Ectopic enterobiasis (migration outside the intestinal tract) is rare but can be serious and may require surgical intervention 3
- In cases of appendicitis where E. vermicularis is found, anthelmintic treatment should be given post-appendectomy 7