Collagenous gastritis in pediatric patients with severe follicular pangastritis and iron deficiency anemia

Abstract Collagenous gastritis is a rare disorder characterized by subepithelial collagen deposition in the gastric mucosa and is frequently associated with iron deficiency anemia. We report two girls aged 8 and 16 years with persistent iron deficiency anemia, abdominal pain, bloating, and constipation. Upper endoscopy revealed severe follicular pangastritis in both patients. Histopathology demonstrated collagenous gastritis, with subepithelial collagen bands measuring 23 and 18 μm, respectively, accompanied by eosinophilic infiltration and absence of Helicobacter pylori infection. One patient had a history of cow's milk allergy and autoimmune family history, whereas the second had positive celiac serology with negative HLA‐DQ2/DQ8. Individualized management included dietary modification, iron replacement, proton pump inhibitor therapy, systemic corticosteroids in one patient, and oral budesonide in the other. Both patients showed clinical improvement and recovery from iron deficiency anemia. These cases highlight collagenous gastritis as an important diagnostic consideration in children and adolescents with refractory iron deficiency anemia and follicular pangastritis.