S0450 Clinical, Endoscopic, Histologic Benefit With Use of Comprehensive Atopy Patch Testing in Adults With Eosinophilic Esophagitis

INTRODUCTION: Atopy patch tests, though not standard of care, have been used to search for eosinophilic esophagitis (EoE) hypersensitivity triggers. We employed type IV allergy patch testing to determine if identification and elimination of aeroallergens and additives to food/consumer products might improve EoE. METHODS: We conducted a retrospective analysis of 18 adult patients at our academic medical center with EoE who underwent type IV allergy patch testing after not responding to 8 weeks of PPI therapy. The primary aim was to determine whether these patients had improvements in symptoms and on surveillance endoscopy 6 to 12 months after avoiding allergens identified on type IV testing. We collected information including demographics, atopic background, symptoms in clinic, patch testing results, endoscopy findings, and pathology. Follow up office visits and endoscopy were reviewed for evidence of clinical, endoscopic, and/or histologic improvement. Bivariate analyses were used to analyze pre-and post-APT patient symptoms, endoscopic severity measured by Composite EoE Endoscopic Reference Scores (EREFS), and improvement in peak eosinophils per high-power field [eos/HPF]. RESULTS: Our cohort was more likely to be younger men with an allergic background (66.7%) presenting with symptoms of dysphagia (66.7%), food impactions (33.3%), and/or heartburn (50%). On initial endoscopy, the average eosinophils/high powered field (HPF) was 31 with mean modified EREFS score of 1.8 (Table 1). 88.9% of patients had positive type IV allergy testing, with 61.1% positive for chemicals/dyes/preservatives, 55.6% for food additives, and 38.9% for aeroallergens. The most commonly positive allergens were Fragrance Mix 1 (including cinnamyl) [25%], cinnamic aldehyde [25%], gold sodium thiosulfate [18.8%], carmine [18.8%], and balsam of peru [12.5%] (Table 2). 11/12 patients adhered to the provided diet and food avoidance strategies with 8/11 (72.7%) reporting improved symptoms. Seven adherent patients followed up for EGD, and 71% had improvement in EREFS of which 57% had histologic improvement. There was a statistically significant decrease in peak eosinophil count post-APT (Figure 1). CONCLUSION: We conclude that the use of type IV allergy skin testing is a viable method to identify food additives and aeroallergens, and avoidance of these allergens with diet/lifestyle modifications can lead to clinical, endoscopic, and histologic improvement of EoE in a PPI refractory population.Table 1Table 2Figure 1.: (A) Statistically significant improvement in peak eosinophil count after atopy patch testing (APT) guided diet/lifestyle modifications. Dashed lines reflect median value. (B) Improvement in Eosinophilic Esophagitis Endoscopy Reference Score (EREFS) after APT-guided diet/lifestyle modification, not statistically significant. Dashed lines reflect median value. (C) Quantified outcomes for EREFS, peak eosinophil count, symptomatic improvement, and histologic response with comparisons made using Wilcoxon Sign-Rank test; IQR (interquartile range), eos/hpf (eosinophils per high-power field).