Muscular and serosal eosinophilic gastritis and enteritis with eosinophilic ascites successfully treated with dupilumab.

Primary eosinophilic gastrointestinal disorders beyond the esophagus (EGIDs) are rare, predominantly Th2-mediated inflammatory conditions, affecting various segments of the gastrointestinal tract. We report the case of a 12-year-old boy with recurrent abdominal pain, peripheral eosinophilia, and progressive gastritis, duodenitis, and enteritis with eosinophilic ascites. He was diagnosed with extensive EGID with muscular and serosal involvement. He was treated with oral corticosteroids and milk elimination diet, which provided temporary relief, but relapses prompted the addition of dupilumab, which achieved durable remission. To our knowledge, this is the first reported case demonstrating the effectiveness of this monoclonal antibody in EGIDs with serosal involvement and eosinophilic ascites. This case highlights the therapeutic potential of dupilumab in refractory EGID cases involving deeper gastrointestinal layers.