To compare endoscopic and histologic features of pediatric patients with eosinophilic esophagitis (EoE) responding to proton pump inhibitor (PPI) to those not responding to PPI.Endoscopic reports and photographs of patients with symptoms of esophageal dysfunction and ≥15 eosinophils per high-powered field (eos/hpf) in esophageal biopsies prior to PPI trial were reviewed. Patients were classified as responsive to PPI (PPIREoE) or non-responsive to PPI (PPINREoE) according to response to treatment (<15 eos/hpf) at second endoscopy after 8 weeks.Of the 231 patients (72.3% male) enrolled, 64 (27.7%) were PPI responsive. Edema (77.3% vs. 62.5%, p=0.031) and furrows (69.5% vs. 51.6%, p=0.014) at endoscopy were more frequent in patients not responding to PPI. Higher peak eosinophil count (≥35 eos/hpf) in the middle esophagus (25.1% vs. 12.5%) was more frequent in the group not responding to PPI (p=0.001). Patients with <15 eos/hpf in the middle esophagus at first endoscopy were more likely to respond to treatment with PPI when compared to patients with 15-34 eos/hpf (p=0.004; OR: 3.26; CI 95%: 1.46 - 7.24) and to patients with ≥ 35 eos/hpf (p=0.006; OR: 3.20; CI 95%: 1.39 - 7.41).Edema and furrows at endoscopy and higher peak eosinophil counts in the middle esophagus were significantly more frequent in the group not responding to PPI. Once there were no significant differences in other features between groups it is not possible to differentiate patients with PPIREoE from patients with PPINREoE based on endoscopic and histologic findings.
