If a person with sickle cell disease is infected with parvovirus, the virus that causes fifth disease in children, an aplastic crisis may develop. Bone marrow suddenly stops producing red blood cells, resulting in sudden and severe anemia. During this time, a person will often feel tired, have pale skin, and be short of breath. In severe cases, aplastic anemia can lead to death if the person is not promptly treated with blood transfusions.

About 5 to 10 days after a crisis starts, the bone marrow usually recovers on its own. And red blood cell production returns to its usual rate.

Most aplastic crises occur in children. This condition only occurs once in any given individual.