Esophageal Eosinophilic Infiltration Responds to Proton Pump Inhibition in Most Adults

BACKGROUND & AIMS: Despite consensus recommendations, eosinophilic esophagitis (EoE) is commonly diagnosed upon esophageal eosinophilic infiltration (EEI; based on >= 15 eosinophils per high power field; eo/HPF). We evaluated the prevalence of EEI before and after proton pump inhibitor (PPI) therapy and assessed the accuracy of EEI and pH monitoring analyses. METHODS: Biopsies were taken from the upper-middle esophagus of 712 adults with upper gastrointestinal symptoms who were referred for endoscopy due to upper gastrointestinal symptoms. Patients with EEI were treated with rabeprazole (20 mg, twice daily) for 2 months. EoE was defined by persistent symptoms and >15 eo/HPF following PPI therapy. RESULTS: Thirty-five patients (4.9%) had EEI, of whom 55% had a history of allergies, and 70% had food impaction or dysphagia as their primary complaint. Twenty-six EEI patients (75%) achieved clinicopathological remission with PPI therapy; of these, 17 had GERD-like profile (EEI <35 eo/HPF and objective evidence of reflux, based on endoscopy or pH monitoring), and 9 had EoE-like profile (EEI 35-165 eo/HPF, typical EoE symptoms and endoscopic findings). The PPI response was 50% in the EoE-like profile patients. The PPI-response was 50% in EoE-like profile patients. Likewise, PPI-responsive EEI occurred with normal (33%) and pathologic (80%) pH monitoring. Higher histologic cut-off values improved specificity and positive predictive for EoE (35%-35% for >20 eo/HPF; 46%-39% for >24 eo/HPF; 65%-50% for 35 eo/HPF). CONCLUSIONS: In adults with EEI, 75% of unselected patients and 50% with an EoE phenotype respond to PPI therapy; pH monitoring is poorly predictive of response. Patients with PPI-responsive EEI >35 eo/HPF are phenotypically undistinguishable from EoE patients. EoE might be overestimated without clinical and pathologic follow-up of patient response to PPI.