Iron deficiency is a relatively common disorder with systemic consequences, especially anemia.
Common causes of a true iron deficiency:
(1) inadequate intake
(2) increased blood loss (chronic GI bleeding, menses, parasites, blood donation)
(3) malabsorption (celiac disease, H. pylori, Crohn's disease, etc)
(4) increased requirements in excess of body stores (such as pregnancy)
Drugs may contribute to iron deficiency by causing malabsorption and/or increased blood loss.
Defects in iron utilization (often with normal or elevated total body iron):
(1) autoantibody against the transferrin receptor
(2) ferroportin deficiency
(3) hereditary atransferrinemia
(4) defective iron-reutilization syndrome
(5) mutation in TMPRSS6 (resulting in excess hepcidin)
(6) anemia of chronic disease
These may give rise to IRIDA (iron refractory iron deficiency anemia).
