• Six-food elimination diet
• EoE

Eosinophilic esophagitis (EoE) is a chronic, immune-mediated, progressive disease of the esophagus triggered by food and possibly inhaled antigens penetrating through a defective esophageal mucosal barrier. Several studies have shown that food triggers esophageal eosinophilia in EoE, while food avoidance leads to the resolution of the eosinophilic infiltrate in most patients. The six-food elimination diet (SFED), represents the most restrictive empiric elimination diet, and has been shown to induce remission in up to 72.1% of EoE patients. evidence on whether inhaled aeroallergens play a role in the esophageal inflammation in EoE is conflicting. In this study, we hypothesized that pollens contribute to the failure of SFED in adult patients with EoE. Accordingly, we compared SFED outcomes during and outside of the pollen season in adult EoE patients with or without sensitization to pollens on skin prick test (SPT). We compared outcomes of EoE patients who underwent SFED during versus outside of the pollen season. Consecutive adult patients with EoE who underwent SFED and skin prick test (SPT) for birch and grass pollen were included. Individual pollen sensitization and pollen count data were analysed to define whether each patient had been assessed during or outside of the pollen season following SFED. All patients had active EoE (≥15 eos/HPF) before SFED and adhered to the diet under the supervision of a dietitian. Fifty-eight patients were included, 62.0% had positive SPT for birch and/or grass, while 37.9% had negative SPT. Overall, SFED response was 56.9%, (95% CI, 44.1%-68.8%). When stratifying response according to whether the assessment had been performed during or outside of the pollen season, patients sensitized to pollens showed significantly lower response to SFED during compared to outside of the pollen season (21.4% vs 77.3%; p=0.003). Additionally, during the pollen season, patients with pollen sensitization had significantly lower response to SFED compared to those without sensitization (21.4% vs 77.8%; p=0.01).Pollens may have a role in sustaining esophageal eosinophilia in sensitized adults with EoE despite avoidance of trigger foods. SPT for pollens may identify patients less likely to respond to the diet during the pollen season.