Red dots of bleeding under the skin. Ulcers in the mouth, throat and rectum. Bone marrow is often infiltrated with fat cells, which supplant areas that manufacture blood cells.
Infections occur because of reduced white cells, which normally protect against infection.
Half of all cases are caused by drugs, especially immunosuppressive drugs, anticancer drugs, chloramphenicol or chemicals such as benzene. Other cases probably result from immunodeficiency, severe illness or unidentifiable causes. Use of drugs listed as causes. Recent severe illness. Don't use drugs that cause aplastic anemia if substitute drugs are available.