Aplastic Anemia

Aplastic anemia.
This is a life-threatening anemia caused by a decrease in the bone marrow's ability to produce all three types of blood cells — red blood cells, white blood cells and platelets. Many times, the cause of aplastic anemia is unknown, but it's believed to often be an autoimmune disease. Some factors that can be responsible for this type of anemia include chemotherapy, radiation therapy, environmental toxins, pregnancy and lupus.
Anemias associated with bone marrow disease. A variety of diseases, such as leukemia and myelodysplasia, a pre-leukemic condition, can cause tive disorders and lymphoma, can cause anemia.
Hemolytic anemias. This group of anemias develops when red blood cells are destroyed faster than bone marrow can replace them. Certain blood diseases can cause increased red blood cell destruction. Autoimmune disorders can cause your body to produce antibodies to red blood cells, destroying them prematurely. Certain medications, such as some antibiotics used to treat infections, also can break down red blood cells. Hemolytic anemias may cause yellowing of the skin (jaundice) and an enlarged spleen.
Sickle cell anemia. This inherited and sometimes serious anemia, which affects mainly people of African and Arabic descent, is caused by a defective form of hemoglobin that forces red blood cells to assume an abnormal crescent (sickle) shape. These irregular-shaped red blood cells die prematurely, resulting in a chronic shortage of red blood cells. Sickle-shaped red blood cells can also block blood flow through small blood vessels in the body, producing other, often painful, symptoms.
Other anemias. There are several other, rarer forms of anemia, such as thalassemia and anemias caused by defective hemoglobin.