- Iron Deficiency Anemia. This form of anemia most common. The heavy periods and a diet low in iron are the most common causes in women. Blood loss through the digestive tract is another common cause of this anemia. Iron deficiency anemia affects the size of red blood cells, which become smaller than normal (microcytic anemia). To learn more, read our fact sheet iron deficiency anemia.
- Anemia caused by vitamin deficiency. This type of anemia produces deformed red blood cells and very large (macrocytic anemia). The most common are those caused by a deficiency in vitamin B12 or vitamin B9 (folic acid). The former may occur because of inadequate dietary intake of this vitamin, its poor absorption in the intestines or a disease called pernicious anemia. For more details, see our handout anemia B12 deficiency.
- Anemia caused by chronic illness. Many chronic diseases (and sometimes their treatment) can reduce the production of red blood cells. This is the case of cancer, Crohn’s disease and inflammatory diseases such as rheumatoid arthritis. Kidney failure can also cause anemia because the kidneys produce erythropoietin, the hormone that stimulates red blood cell production. They still retain their size and look normal (normocytic anemia).
- Hemorrhagic anemia. Blood loss can cause anemia. Heavy periods, childbirth or loss of blood in the stool (often invisible) due to gastro-intestinal problems (peptic ulcer, colon polyps or colorectal cancer).
- Hemolytic anemia. This type of anemia is characterized by a too rapid destruction of red blood cells. It may be due to an immune system (autoimmune or allergic), presence of toxins in the blood, infections (eg malaria), or be congenital (sickle cell anemia, thalassemia, etc). The congenital form affects mostly people of African descent.
- Sideroblastic anemia. The term umbrella group of very rare anemia where red blood cells can not set the iron in hemoglobin. This is a problem enzymatic hereditary or acquired. Red blood cells are smaller than normal.
- Aplastic anemia (or aplastic). This rare condition occurs when bone marrow stops producing enough blood stem cells. Thus, it is not only a lack of red blood cells, but also white blood cells and platelets. In 50% of cases, aplastic anemia is caused by toxins, certain drugs or exposure to radiation. It can also be explained by serious diseases such as leukemia.