Iron deficiency anemia in celiac disease.

Iron is an important micronutrient that may be depleted in celiac disease. Iron deficiency and anemia may complicate well-established celiac disease, but may also be the presenting clinical feature in the absence of diarrhea or weight loss. If iron deficiency anemia occurs, it should be thoroughly evaluated, even if celiac disease has been defined since other superimposed causes of iron deficiency anemia may be present. Most often, impaired duodenal mucosal uptake of iron is evident since surface absorptive area in the duodenum is reduced, in large part, because celiac disease is an immune-mediated disorder largely focused in the proximal small intestinal mucosa. Some studies have also suggested that blood loss may occur in celiac disease, sometimes from superimposed small intestinal disorders, including ulceration or neoplastic diseases, particularly lymphoma. In addition, other associated gastric or colonic disorders may be responsible for blood loss. Rarely, an immune-mediated hemolytic disorder with increased urine iron loss may occur that may respond to a gluten-free diet. Reduced expression of different regulatory proteins critical in iron uptake has also been defined in the presence and absence of anemia. Finally, other rare causes of microcytic anemia may occur in celiac disease, including a sideroblastic form of anemia reported to have responded to a gluten-free diet.