Clinicopathologic Analysis of Proton Pump Inhibitor-Responsive Esophageal Eosinophilia in Korean Patients

BACKGROUND/AIMS Proton pump inhibitor-responsive esophageal eosinophilia (PPI-REE) is a newly recognized form of eosinophilic esophagitis (EoE) that responds to PPI therapy. It remains unclear whether PPI-REE represents a subphenotype of gastroesophageal reflux disease, a subphenotype of EoE, or its own distinct entity. The aim was to evaluate the clinicopathologic features of PPI-REE. METHODS Six patients were diagnosed with PPI-REE based on symptoms, endoscopic abnormalities, esophageal eosinophilia with ≥15 eosinophils/high-power field, and a response to PPI treatment. Symptoms and endoscopic and pathological findings were evaluated. RESULTS The median follow-up duration was 12 months. Presenting symptoms included dysphagia, heartburn, chest pain, foreign body sensation, acid reflux, and sore throat. All patients had typical endoscopic findings of EoE such as esophageal rings, linear furrows, nodularity, and whitish plaques. Three patients had a concomitant allergic disorder, and one had reflux esophagitis. Four patients exhibited elevated serum IgE, and five had positive skin prick tests. All patients experienced symptomatic resolution within 4 weeks and histologic resolution within 8 weeks after starting PPI therapy. There was no symptomatic recurrence. CONCLUSIONS PPI therapy induced rapid resolution of symptoms and eosinophil counts in patients with PPI-REE. Large-scale studies with long-term follow-up are warranted.