Pinworm infestation, also known as enterobiasis, is a common parasitic infection caused by the nematode Enterobius vermicularis.

  • Primarily affects children and spreads via the fecal-oral route.
  • Main symptom is perianal itching, especially at night.
  • Bacterial superinfections can result from scratching and excoriation of the area.

History and Examination

  • Children aged 5-14 years, close contacts with infected individuals, visualization of worm in perianal region , 2 to 3 hours child is asleep
  • Risk factors: Poor hygiene, crowded living conditions, daycare or school attendance
SymptomsSigns
-Perianal itching, especially at night
-Restlessness and difficulty sleeping due to itching
-Abdominal pain (less common)		-Visible pinworms around the anus or in stool

Differential Diagnosis (D/D) & Complications

D/D

  • Other causes of perianal itching (fungal infection, contact dermatitis, hemorrhoids)
  • Other parasitic infections (ascariasis, hookworm)

Complications

  • Secondary bacterial infections due to scratching
  • Urinary tract infections (rare)
  • Appendicitis (rare), worm reside in appendix lumen

Investigation

  • Investigation of choice: Scotch tape test (collecting pinworm eggs from the perianal area, preferably in the morning before bathing)
  • Stool examination for ova and parasites (No egg shedding occurs inside the intestinal lumen; thus, very few ova are present in stool, so examination of stool specimens for ova and parasites is not recommended)
  • CBC: Low hemoglobin, microcytic hypochromic anemia. Eosinophilia is unusual in pinworm infection.

Admission Criteria

  • Generally not required, as pinworm infestation is usually managed on an outpatient basis

Management

Medical

  • Anthelmintic therapy for the affected child and close contacts

Rx:

  1. Albendazole 400 mg single dose, repeated after 2 weeks Or,
  2. Mebendazole 100 mg single dose, repeated after 2 weeks (DOC) or,
  3. Pyrantel pamoate 11mg/kg base three times a day PO (maximum 1g) repeated after 2 weeks or,
  4. Mebendazole 100mg PO BD x 3 days

Reinfection with pinworms occurs easily; prevention should be discussed when treatment is given.

Advices

  • Patient should bath in the morning as it removes large portion of eggs.
  • Change the infected person’s underclothes, bedclothes, and bed sheets to decrease egg contamination and risk of reinfection
  • Washing bed linens and clothing in hot water
  • Good hygiene practices (handwashing, keeping nails short, avoiding scratching)

Referral

  • If the infestation persists despite treatment and adherence to hygiene measures

Follow up

  • Schedule a follow-up visit within 4 weeks after treatment completion
  • Assess for resolution of symptoms and signs of reinfection

References

1. American Academy of Pediatrics. Red Book: 2018-2021 Report of the Committee on Infectious Diseases. 31st ed. Elk Grove Village, IL: American Academy of Pediatrics; 2018.

2. Burkhart CN, Burkhart CG. Assessment of frequency, transmission, and genitourinary complications of enterobiasis (pinworms). Int J Dermatol. 2005;44(10):837-840.

3. Cook GC, Zumla AI, eds. Manson’s Tropical Diseases. 23rd ed. Philadelphia, PA: Saunders Elsevier; 2009.