Herpes Simplex Esophagitis Superimposed on Eosinophilic Esophagitis in an Immunocompetent Patient.

Herpes simplex esophagitis (HSE) rarely occurs in immunocompetent patients. Eosinophilic esophagitis (EoE) may predispose to herpes simplex virus superinfection through epithelial barrier disruption. We present an immunocompetent woman with previous EoE managed with dietary modifications without pharmacologic therapy who developed severe odynophagia. Endoscopy showed erosive esophagitis mimicking candidiasis and active EoE, histologically consistent with HSE without eosinophilic inflammation or fungal organisms. Empiric antifungals and corticosteroids were discontinued, and intravenous acyclovir was initiated with rapid improvement. Follow-up endoscopy confirmed complete mucosal healing. This case highlights the diagnostic complexity of HSE complicating EoE and the indispensable role of histopathologic evaluation.