Pinworm Infection Diagnosis and Management

Clinical Presentation and Diagnosis

Nocturnal pruritus ani is the cardinal symptom of pinworm infestation, occurring because female worms migrate to the perianal area at night to deposit eggs, according to the Journal of Infection 1
The excoriations around the anus result from scratching in response to the intense itching, as reported in the Journal of Infection 1
The 2-4 week prepatent period aligns with symptom onset a few days after returning from camp, where transmission occurred during the month-long stay, as noted in the Journal of Infection 1
Pinworms are highly contagious and spread via the fecal-oral route, making transmission in close quarters like summer camp cabins extremely common, according to the Journal of Infection 1
The cellophane tape test (sellotape test) is the diagnostic method of choice, performed by placing the sticky side of tape on the perianal skin in the morning before bathing, then examining it under microscopy for ova, as recommended in the Journal of Infection 1
A single test has approximately 50% sensitivity, but three tests performed on consecutive mornings increase sensitivity to approximately 90%, as reported in the Journal of Infection 1

Giardiasis presents with diarrhea and abdominal cramping, not isolated perianal itching, and would not explain the physical findings, according to MMWR Recommendations and Reports 2
Internal hemorrhoids can cause perianal itching through mucus discharge, but this patient has no palpable hemorrhoid on examination and lacks the typical bleeding or prolapse symptoms, as noted in Gastroenterology 3
Scabies causes generalized pruritus that worsens at night but typically involves the hands, wrists, and web spaces between fingers, not isolated perianal involvement, according to MMWR Recommendations and Reports 2

First-line treatment is mebendazole 100 mg as a single oral dose, repeated in two weeks, as recommended in the Journal of Infection 1
Critical hygiene measures to prevent reinfection include washing hands and fingernails with soap frequently during the day, especially before eating and after using the toilet, as noted in the Journal of Infection 1