AB is a 12-year-old boy with esophageal eosinophilia (72 eosinophils in the distal and 35 in the proximal esophageal sample) identified at the time of an upper endoscopy that was performed to assess for abdominal pain. The endoscopic report and images demonstrated esophageal furrowing, friability and distal ulcerations. Because of this finding, he was treated with fluticasone 220 ug 2 puffs swallowed twice a day. He experienced no relief of his symptoms. Upon referral, his history was notable for daily heartburn and regurgitation. pH impedance monitoring of the esophagus documented an elevated reflux index of 16.3 % and >75% symptom correlation. Treatment with omeprazole 20 mg QD brought symptom relief.
Over the last few years, a number of studies demonstrated 2 key points regarding esophageal eosinophilia. The first is that this histological finding is associated with a number of different clinical conditions including, and not limited to EoE. Dense esophageal eosinophilia, characterized by >15 eos / HPF can be observed in gastroesophageal reflux disease (GERD), as in this patient, and other conditions. In addition, a new sub-group of patients, who present with esophageal symptoms and have a normal pH impedance probe monitoring of the esophagus, has dense esophageal eosinophilia and both symptoms and tissue findings resolve with proton pump inhibitor (PPI) treatment. This group of patients has been described as having proton pump inhibitor responsive esophageal eosinophilila [--]. Whether they represent a variant of GERD or EoE is not certain. This clinical finding brings us to the second key group of studies that have demonstrated an alternative mechanism that PPIs may impact the GI tract. Whereas the traditional target for PPIs is the proton pump, new data has identified the role of PPIs in inhibiting cytokine responses from esophageal epithelia. In these studies, investigators demonstrate that concentrations of PPIs used for acid inhibition are able to impact the expression and release of cytokines such as IL-8 and eotaxin-3, two cytokines thought to participate in GERD and EoE respectively [--]. Taken together, these studies emphasize the importance of interpreting the histological findings in clinical context of which the biopsies were taken. Friability and ulceration are unusual features of EoE and since GERD is much more common than EoE, an alternative approach would be to treat the patient, regardless of the level of eosinophilia, with a PPI first. Future studies in these areas will need to determine if alternative biomarkers may be able to separate out different causes of esophageal eosinophilia so that appropriate treatments can be initiated early.