Gastrointestinal Eosinophilic Granulomatosis with Polyangiitis following a Infection.

Eosinophilic granulomatosis with polyangiitis (EGPA), historically named Churg-Strauss syndrome, is a rare vasculitis affecting small- and medium-sized blood vessels. The disease has a predilection for numerous organs including the lungs, sinuses, kidneys, heart, nerves, and gastrointestinal tract but is prominently associated with asthma, rhinosinusitis, and eosinophilia. Gastrointestinal involvement is common; however, a gastrointestinal manifestation as the cardinal symptom following an infection is atypical. Here, we present a case of a 61-year-old male who presented with persistent diarrhea following a toxigenic infection despite multiple antibiotic courses. Repeat testing confirmed eradication of the infection, and further evaluation with colon biopsy revealed small and medium-sized vasculitis with eosinophilic infiltration and granulomas. Treatment with prednisone and cyclophosphamide resulted in rapid improvement of his diarrhea. Gastrointestinal symptoms in EGPA are associated with worse prognosis, so prompt identification and treatment of the disease is crucial. EGPA is rarely documented in histopathological samples from the gastrointestinal tract as endoscopic biopsies are typically too superficial to sample the submucosal layer containing the affected vessels. Additionally, the link between EGPA and infections as a potential trigger has not been clearly established, but gastrointestinal EGPA manifesting after a colonic infection raises concerns that this may have been a triggering event. Ultimately, further study is needed to understand, diagnose, and treat gastrointestinal and postinfection EGPA.