Collagen gastritis is a rare disease that manifests in children mainly as isolated gastric involvement associated with martial deficiency anemia. There are no recommendations for the management and follow-up of these patients. We aimed to describe the clinical data, endoscopic findings, and treatments deployed in France's children with collagenous gastritis.

All French pediatric gastroenterology centers and pediatric centers for rare digestive diseases (Centres de Maladies Rares Digestives) were contacted to collect cases of collagenous gastritis, defined on gastric biopsies and diagnosed before 18 years of age.

A total of 12 cases diagnosed (4 males and 8 females) between 1995 and 2022 could be analyzed. The median age at diagnosis was 12.5 years (7–15.2). The most frequent clinical presentation was abdominal pain (6/11) and/or nonspecific symptomatology attributed to anemia (8/10). Anemia was present in all children (11/11; Hb 2.8–9.1 g/dL). Nodular gastritis was present in 10 patients (antrum: 2; fundus: 4; in antrum and fundus: 4). All patients had a basement membrane thickening (from 19 to 100 μm). The treatments received were PPI (11), oral or intravenous martial supplementation (12), budesonide (1), and prednisone (1). Martial supplementation improved anemia in all cases. At discontinuation, nine of 10 patients had a recurrence of anemia.

Collagenous gastritis is an exceptional condition, clinically manifested in children as abdominal pain and iron deficiency anemia probably of hemorrhagic origin. Patients require long-term follow-up and monitoring of their disease to describe the risk of progression better.