n.
Condition in which erythrocytes are reduced in number or volume or are deficient in hemoglobin .
The patient is usually noticeably pale. Close to 100 varieties exist (including aplastic anemia , pernicious anemia , and sickle-cell anemia ), distinguished by cause; erythrocyte size, shape, and hemoglobin content; and symptoms. Anemia may result from blood loss; increased destruction, reduced production, or inhibited formation of red cells; or hormone deficiency. Treatment may involve nutrition, toxin removal, drugs, surgery, or transfusion. See also folic-acid-deficiency anemia , iron-deficiency anemia .