Peripheral Eosinophilia Found in Pediatric Enterobius vermicularis Infections

Enterobius vermicularis, the common pinworm, is well known in North America as a parasitic infection, mainly affecting children. It is a very contagious organism, and it is responsible for a high number of infections in the United States each year. A rise in eosinophilia is linked to most parasitic infections. However, the correlation between eosinophilia and enterobiasis infections is not well documented in the literature. In this article, we present 3 cases involving patients seen for pediatric gastroenterology consultation with concern for inflammatory bowel disease. As part of their evaluation, each patient was found to have eosinophilia of unknown significance with an ultimate diagnosis of pinworm infections made by endoscopy. Their illness presentation did not include classic enterobiasis symptoms such as rectal pruritus or nighttime irritability. These cases support a link between eosinophilia and enterobiasis that may be instructive for pediatric providers seeing patients with eosinophilia for which there is no readily apparent underlying cause.