Do Pinworms Cause Eosinophilic Esophagitis?

Abstract

Introduction: Eosinophils are found in the gastrointestinal tract with the exception of the esophagus. Their location allows access to defend against parasitic infections. Upon activation, eosinophils release granules/cellular products to kill parasites to large for phagocytosis. Eosinophilic esophagitis (EE) clinically results in heartburn, abdominal pain and vomiting, and most children with EE are atopic. Diagnosis is supported by an esophageal biopsy findings of > 15 eosinphils/hpf. Enterobius vermicularis infection is characteristically mild with symptoms of perianal pruritis secondary to egg deposition. Peripheral eosinophilia is an uncommon feature. There are case reports of eosinophilic ileocolitis, gastroenteritis and appendicitis secondary to pinworm infestation. However, there are no case reports of EE associated with pinworm infestation. Case Discussion: A 12 year old male presented with recurrent abdominal pain for 2 years. A sledding accident resulted in a CT scan, showing thickening of the colon. A CBC revealed 21% eosinophils. A esophagogastroduodenoscopy and colonic endoscopy with biopsies revealed 20 eosinophils/hpf in the esophagus, chronic gastritis with eosinophils, and chronic duodenal inflammation with eosinophils. Pinworms were visualized during colonoscopy. Stools testing for other parasites and celiac testing were negative. Skin testing was positive to milk, egg, peanut and beef. Patient was treated for pinworms, started on Budesonide 500mcg swallowed twice daily, food restriction based on positive skin testing, and Prevacid 15mg twice daily. Repeat biopsy 3 months later on therapy was negative for eosinophils in all biopsy specimens, and the lower endoscopy was negative visually for pinworms. Eosinophils 2% on repeat CBC. Discussion: Elimination of pinworms and proper treatment for EE has resulted in both clinical and pathological improvement. The question remains as to whether pinworms can elicit an eosinophilic-based immune response in the esophagus. Since the lifecycle of Enterobius vermicularis involves the entire GI tract (eggs ingested travel to bowel where they hatch, grow and deposit new eggs around anus), it is logically to conclude that certain individuals could have an eosinophil response in the esophagus to the ingested eggs. Removal of the offending allergen would then result in resolution of EE.