Esophageal String Test Monitoring to Monitor Eosinophilic Esophagitis During Oral Immunotherapy

The goal of this study is to investigate the EST as a screening tool for EoE during OIT therapy. Investigators will utilize these tools to screen patients at their baseline visit prior to the start of OIT, then at the 3- and 6-month OIT follow-up visits. The primary objectives are to assess feasibility of the EST as a screening tool for EoE in IgE mediated food allergy patients in an OIT program. The secondary objective(s) are to: (1) estimate the correlation of EST and PEESS in screening for EoE in IgE mediated food allergy patients in an OIT program, (2) provide an estimate of the prevalence of EoE in IgE mediated food allergy patients, which Investigators will measure at the time of presentation for OIT, (3) provide an estimate of the incidence of development of EoE during the first 3- and 6- months of OIT. The study will take place at the Children's Hospital of Philadelphia Food Allergy Clinic sites that participate in OIT. There will be 75 participants ages 7-18 years of age with IgE mediated food allergy who are undergoing oral immunotherapy for food allergies.