D3.189 - Oral Immunotherapy–Associated Eosinophilic Esophagitis: A Pediatric Case Report

Oral Immunotherapy Associated Eosinophilic Esophagitis: A Pediatric Case Report

M. Jurić¹, I. Mrkić Kobal¹˒², A. Miletić Gospić¹, I. Marić¹, D. Erceg¹˒²˒³, M. Turkalj¹˒²˒³¹ Srebrnjak Children’s Hospital, Zagreb, Croatia² Faculty of Medicine, J. J. Strossmayer University of Osijek, Osijek, Croatia³ Catholic University of Croatia, Zagreb, Croatia

BackgroundEosinophilic esophagitis (EoE) is a chronic immune-mediated disease characterized by symptoms of esophageal dysfunction and eosinophil-predominant inflammation (≥15 eosinophils per high-power field, ~0.3 mm²). In children, symptoms are often nonspecific, including feeding difficulties, vomiting, and impaired growth. Although established EoE is considered a contraindicates oral immunotherapy (OIT), de novo EoE emerges as a common adverse event during OIT, typically responsive to treatment.

Clinical CaseA 7-year-old boy with polysensitization to multiple food and inhalant allergens was evaluated (total IgE 785 kIU/L, f233 [Gal d 1, ovomucoid] = 39, f1 = 75.60, f75 = 4.31). Due to persistent egg allergy and early reactions (urticaria, vomiting), a baked egg OIT protocol was planned. Prior to OIT, a double-blind placebo-controlled food challenge was performed. After ingestion of 30 mg of egg protein, the patient developed sneezing, nausea, abdominal pain, and generalized urticaria, requiring intramuscular adrenaline. OIT was initiated at the last tolerated dose (0.3 mg egg protein) with 25% dose escalation every 3–4 weeks.

After three months of OIT, the patient developed persistent dysphagia. Upper gastrointestinal endoscopy with esophageal biopsy confirmed EoE, demonstrating 30 eosinophils per high-power field. OIT was discontinued, egg elimination was reinstated, and the patient remains under gastroenterological follow-up. This was the sole case of EoE among 71 patients undergoing baked egg OIT (incidence: 1.4%).

ConclusionsEoE should be evaluated in OIT patients with persistent gastrointestinal symptoms. Although rare, OIT-associated EoE represents a clinically relevant adverse event. Baked egg protocols seem safer regarding EoE than conventional egg protocols. Structured screening tools and validated questionnaires may facilitate earlier recognition and improve clinical outcomes.