The purpose of this review is to evaluate the existing information on the development of eosinophilic esophagitis (EoE) in people who are receiving oral and sublingual immunotherapy (SLIT) for food and environmental allergies. The cumulative incidence of EoE in individuals receiving peanut, milk, and egg allergy immunotherapy is estimated. On the scale of case reports and prospective randomised trials, de novo development of EoE in patients undergoing oral and SLIT has been observed. However, few people who experience EoE-like symptoms while receiving immunotherapy get endoscopies, and the long-term effects of immunotherapy-associated EoE remain unknown.

There is evidence that allergen immunotherapy may put people at risk of developing EoE, the true incidence of which may vary depending on antigen exposure and the methods used to characterise the illness.

Reference: https://journals.lww.com/co-allergy/Abstract/2019/08000/Eosinophilic_esophagitis_during_sublingual_and.13.aspx