Literature Review and a Relevant Case of Pediatric Collagenous Gastritis: A Rare but Important Etiology of Iron-Deficiency Anemia.

An adolescent male with fatigue, weight loss, and iron-deficiency anemia failed to improve with iron supplementation and a gluten-free diet. Endoscopy revealed collagenous gastritis. Pediatric patients with refractory iron deficiency and family history of autoimmune disorders should be referred to pediatric gastroenterology for evaluation of collagenous gastritis and celiac disease.