Normal red blood cells have a 120-day life span, but people born with sickle cell disease have sickle-shaped blood cells that usually live no more than 20 days. These sickled cells can get stuck in blood vessels, blocking blood flow. See an illustration of sickle cells blocking a blood vessel.

Lesser blood flow can damage the body's organs, muscles, and bones, sometimes leading to life-threatening conditions. Sickle cell disease may cause:

• Vaso-occlusive complication (painful event), which results when blood vessels are blocked. This is a common condition of sickle cell disease.
• Splenic sequestration, usually seen in children age 6 months to 2 years during or after a simple respiratory infection. In this situation, large numbers of sickled red blood cells become trapped in the spleen. It can cause sudden and life-threatening anemia.
• Acute chest syndrome, most common in children but more severe in adults. Coughing and chest pain are symptoms of acute chest syndrome, which may occur after an infection or painful event.
• Severe infections, particularly in children younger than 3.
• Aplastic crisis, which may occur after infection with some viruses. During an aplastic crisis, bone marrow stops producing red blood cells, resulting in sudden and severe anemia.

When a child is born with sickle cell disease, it's impossible to predict which problems will develop, when they will start, or how severe they will be. During the first 6 months of life, infants have a high level of fetal hemoglobin (HbF) in their blood, which protects them from red blood cell sickling. However, dangerous complications of sickle cell disease may quickly develop between the ages of 6 months and 5 years, after levels of fetal hemoglobin decrease. Normal red blood cells have a 120-day life span, but sickled blood cells usually live no more than 20 days. When bone marrow can't produce enough red blood cells to keep up with sickled blood cell loss, severe anemia may develop.

Older children and adults with sickle cell disease may have few problems or have a pattern of ongoing complications that shortens their lives. The most common and serious problems caused by sickle cell disease are anemia, pain, and organ failure.³ Stroke affects around 10% of children with sickle cell disease.⁴

Other complications of sickle cell disease include:

• Severe infections, especially in children younger than 3. Children with sickle cell disease are at risk for sudden, life-threatening infections.
  • Children require standard immunizations and pneumococcal and flu shots. In addition, children younger than 5 need to take a daily antibiotic, such as penicillin, to prevent infection.⁵ For more information, see the topic Immunizations.
• Growth slowdown. Children with sickle cell disease often grow more slowly than normal and go through puberty later than children who don't have sickle cell disease.
• Open sores (ulcers) on the legs and feet, commonly during adulthood. These ulcers can be very painful and heal slowly. Some may last for years.
• Eye damage. Long-term vision problems may result from blocked blood flow in the inner lining of the eye (retina).

The average age at death for people with sickle cell disease has been 42 for men and 48 for women.⁶ However, the overall life expectancy for people with sickle cell disease is improving. Some people with sickle cell disease live past the age of 70.⁷