OMEGA: Outcome Measures in Eosinophilic Gastrointestinal Disorders Across the Ages

Inclusion Criteria: * Males or females 3 years of age and older * Mucosal eosinophilia: EoE ≥ 15 eosinophils/HPF in the distal or proximal esophagus EoG ≥ 30 eosinophils/HPF in 5 HPF\'s in the body and/or antrum EoN ≥ 53 eosinophils/HPF in the duodenum and/or ≥ 56 eosinophils/HPF in the jejunum and/or ileum EoC ≥ 84 eosinophils/HPF from the transverse or descending colon and/or ≥ 32 eosinophils/HPF from the rectosigmoid colon or a biopsy from any colonic location with ≥ 100 eosinophils/HPF \- Presence of symptoms is required for patients who are newly diagnosed but not required for patients who were previously diagnosed. Exclusion Criteria: * History of intestinal surgery other than G tube placement * Enrolled in a blinded investigational study at the time of the first study visit * Have esophageal stricture (\<3mm) * Have other identifiable causes for eosinophilia (except Inflammatory Bowel Disease): infections, Gastrointestinal (GI) cancer, other GI inflammatory disease (e.g., Ulcerative Colitis or Crohn\'s Disease)