Abstract
BACKGROUND: Non-esophageal eosinophilic gastrointestinal disorder (non-EoE-EGID) is a rare disease in which eosinophils infiltrate parts of the gastrointestinal tract other than the esophagus; however, the number of patients with non-EoE-EGID has been increasing in recent years. Owing to its chronic course with repeated relapses, it can lead to developmental delays due to malnutrition, especially in pediatric patients. No established treatment exists for non-EoE-EGID, necessitating long-term systemic corticosteroid administration. Although the efficacy of dupilumab, an anti-IL-4/13 receptor monoclonal antibody, for eosinophilic esophagitis, has been reported, only few reports have demonstrated its efficacy in non-EoE EGIDs. CASE PRESENTATION: A 13-year-old boy developed non-EoE-EGID with duodenal ulcers, with chicken eggs as the trigger. He was successfully treated with an egg-free diet, proton pump inhibitors, and leukotriene receptor antagonists. However, at age 15, he developed worsening upper abdominal pain and difficulty eating. Blood analysis revealed eosinophilia; elevated erythrocyte sedimentation rate; and elevated levels of C-reactive protein, total immunoglobulin E, and thymic and activation-regulated chemokines. Upper gastrointestinal endoscopy revealed a duodenal ulcer with marked mucosal eosinophilic infiltration. Gastrointestinal symptoms persisted even after starting systemic steroids, making it difficult to reduce the steroid dose. Subcutaneous injection of dupilumab was initiated because of comorbid atopic dermatitis exacerbation. After 3 months, the gastrointestinal symptoms disappeared, and after 5 months, the duodenal ulcer disappeared and the eosinophil count decreased in the mucosa. Six months later, systemic steroids were discontinued, and the duodenal ulcer remained recurrence-free. The egg challenge test result was negative; therefore, the egg-free diet was discontinued. Blood eosinophil count and serum IL-5, IL-13, and eotaxin-3 levels decreased after dupilumab treatment. The serum levels of IL-5 and eotaxin-3 remained within normal ranges, although the blood eosinophil counts increased again after discontinuation of oral prednisolone. CONCLUSIONS: Suppression of IL-4R/IL-13R-mediated signaling by dupilumab may improve abdominal symptoms and endoscopic and histologic findings in patients with non-EoE-EGID, leading to the discontinuation of systemic steroid administration and tolerance of causative foods.