Endoscopic and histologic findings in a patient with dysphagia and esophageal eosinophilic infiltration before PPI therapy (top panel) and after therapy (bottom panel). Courtesy of J. Molina-Infante.

“Eosinophilic esophagitis (EoE) is an emerging and intriguing allergic disease, no doubt, but lately it has possibly been overdiagnosed in the absence of a PPI trial” says Javier Molina-Infante, lead author of a recent Spanish study.

EoE is often diagnosed on the basis of evidence of esophageal eosinophilic infiltration (EEI) alone, despite recommendations of consensus guidelines to perform a PPI trial to preclude a diagnosis of GERD. Molina-Infante and colleagues studied the prevalence of EEI before and after PPI therapy in patients with suspected EoE on the basis of histologic findings. The adequacy of pH monitoring to preclude a diagnosis of GERD was also assessed. Patients were recruited from a single Spanish hospital.

In a group of 35 adults with EEI at baseline, 75% responded to PPI therapy and 35% of these responders had typical symptoms and endoscopic findings compatible with EoE. Importantly, patients with PPI-responsive EEI and an eosinophil count of >35 eosinophils per high power field were phenotypically indistinguishable from patients with EoE. In addition, 33% of patients with normal findings on pH monitoring had PPI-responsive EEI.

“This striking finding is far from current thinking that these patients are suffering from GERD”, says Molina-Infante. He believes that there may be a subtype of EoE patients, without GERD, who may be responsive to PPI therapy. “If this is the case, we would be talking about anti-inflammatory or immunomodulatory novel effects of PPIs, beyond acid suppression, responsible for the remission observed in these patients,” he explains.

The group is now conducting a prospective study to try to elucidate molecular and genetic markers involved in this intriguing effect of PPIs on allergic diseases such as EoE.