Strict cow's milk-free diet is effective to treat oral immunotherapy-related eosinophilic esophagitis

Eosinophilic esophagitis (EoE) is a chronic inflammatory disease of the esophagus due to an immunoallergic pathogenesis. Therapy includes antigen-free diet and topical steroid treatment. EoE has been described as a rare complication of food oral immunotherapy (OIT). We herein report the case of a 15-year-old boy who developed EoE after cow's milk OIT. He was diagnosed with cow's milk protein allergy (CMPA) at the age of 3 months. He underwent a milk OIT at the age of 10 due to persistence of milk allergy. Buildup phase went on slowly due to recurrent reactions characterized by abdominal pain, oral itching, and transient skin rash. Nevertheless, at the age of 12, he managed to achieve a free diet, with daily ingestion of about 200 mL of fresh milk. Three years later, he began experiencing nighttime epigastric pain and heartburn. An eight- week treatment with high-dose proton pump inhibitors was performed three times, failing to induce persistent remission of symptoms. Thus, he underwent an esophagogastroduodenoscopy (EGDS) which showed macroscopic and histological signs of EoE (≥ 15 eosinophils/high power field). At the 12 months follow-up, after a cow's milk-free diet that allowed the ingestion of baked milk products, he achieved clinical, but not histological, remission. No pharmacological treatment was administered. Therefore, a strict cow's milk-free diet was started. A second follow-up was performed 12 months later, showing persistence of clinical remission, and EGDS revealed a complete macroscopic and histological resolution. Strict elimination diet, without any pharmacological treatment, is effective to treat milk OIT-related EoE.