Chronic Diarrhea and Abdominal Pain: Pin the Pinworm

Enterobius vermicularis is the most common helminthic infection in the US. It is usually considered an innocuous parasite that at the most causes perianal itching. We report a case of an 84-year-old female patient from an assisted living facility who presented with symptoms of colitis for 2 months. On detailed history and exam, she was found to have E. vermicularis infection. All her symptoms resolved dramatically within 2 days after a single dose of albendazole. We want to emphasize the importance of including parasitic infections such as E. vermicularis in the differential diagnoses of patients presenting with symptoms of colitis.