Dupilumab Versus Topical Corticosteroid Effectiveness - Comparison in the Treatment of Stenotic EoE

Inclusion Criteria: * Seen at CHCO for clinical care. * Age 12 - 25 years old inclusive * Weight ≥40 kg at the time of screening visit * Confirmed EoE as diagnosed by biopsy with eosinophils ≥15 eosinophils/hpf in at least 2 esophageal regions at screening endoscopy * Report of an average of at least 2 episodes of dysphagia per week in the 4 weeks prior to screening. * Evidence of fibrostenotic features at time of screening endoscopy (grade 2 or 3 esophageal rings, stricture, delayed passage of barium tablet on fluoroscopy, and/or distensibility ≤15mm) Exclusion Criteria: * Esophageal dilation performed at index endoscopy * Patients with stricture undergoing dilation at index endoscopy may be rescreened if they meet all other eligibility criteria. * Patients with acute food impaction will not be enrolled at their therapeutic endoscopy but are eligible for enrollment subsequently if they meet all other eligibility criteria. * Eligible patients on current STCs can be enrolled but need to be on stable dosing less than or equal to 440 mcg two times daily fluticasone equivalent for 3 months prior to enrollment. * Patients who have received dupilumab in the past 12 months for any indication are excluded. * Diet restrictions and PPI use must stay unchanged in the 8 weeks prior to index endoscopy and through the study period. * Patients with a fasting morning cortisol \<5 within 2 months of screening will not be enrolled. If repeat cortisol levels are normal, patients can be reconsented. * Known other esophageal disease or esophageal injury (e.g. achalasia, tracheoesophageal fistula, congenital stricture, caustic injury, history of esophageal surgery), inflammatory bowel disease, liver disease, connective tissue disorder, or bleeding disorder. * Patients with a known gelatin allergy will be excluded from EST collection.