Sickle cell disease (SCD) is an inherited blood disorder that affects the shape and movement of red blood cells. Instead of being round and flexible, red blood cells in people with SCD are curved (sickle-shaped) and stiff. This abnormal shape makes it difficult for them to move smoothly through blood vessels, disrupting oxygen delivery throughout the body.

When sickle-shaped cells clump together, they block small blood vessels. This can lead to organ damage, severe pain, fatigue, and frequent infections. Although there is no permanent cure, treatments can reduce symptoms and improve quality of life.

SCD disproportionately affects people of African descent, with about one in 365 African American children in the United States born with the condition. It also occurs in higher numbers among people of Hispanic, Middle Eastern, and Indian descent.

Types Of Sickle Cell Disease

The type of SCD you have depends on which genes you inherit from your parents.

hemoglobin ss (hbss): Also called sickle cell anemia, this type occurs when both parents pass down the hemoglobin S gene. It is the most common and severe form.

hemoglobin sc (hbsc): Caused by inheriting the hemoglobin S gene from one parent and the hemoglobin C gene from the other. Symptoms are generally milder than HbSS.

hbs beta thalassemia: Combines hemoglobin S with another blood disorder called beta thalassemia.

  • Beta zero means no healthy hemoglobin is made, leading to more serious complications.

  • Beta plus allows partial production of healthy hemoglobin, so symptoms are usually milder.

rare forms: HbSD, HbSE, and HbSO occur when hemoglobin S is inherited from one parent and another unusual hemoglobin gene (such as D, E, or O) from the other parent.

Symptoms Of Sickle Cell Disease

Symptoms vary by age, type of SCD, and treatment frequency. Some people develop symptoms in infancy, while others experience milder or more delayed complications.

common symptoms include:

  • Pain in joints, bones, or abdomen

  • Fatigue and weakness

  • Anemia (low red blood cell count)

  • Yellowing of skin or eyes (jaundice)

  • Swelling in hands and feet (dactylitis)

  • Priapism (painful, prolonged erections in males)

  • Frequent infections due to spleen damage

  • Delayed growth and puberty in children

What Causes Sickle Cell Disease?

Sickle cell disease is a genetic condition passed down from parents to children. A person must inherit two sickle cell genes—one from each parent—to develop the disease.

inheriting from one parent: If only one parent passes on the gene, the child will have sickle cell trait but not the disease. People with the trait usually do not experience symptoms but can pass the gene to their children.

Risk Factors

SCD can affect anyone, but it is most common among people of African, Hispanic, Middle Eastern, and Indian descent. The risk increases when both parents carry the sickle cell trait.

Diagnosis

SCD is usually diagnosed with a blood test. In the United States, newborns are routinely screened.

newborn screening: A small blood sample from the baby’s heel is tested for sickle cell trait and other conditions. Additional testing may follow at 3–6 months of age.

family history and symptoms: Older children and adults with symptoms or a family history of SCD can request blood or genetic testing to confirm the condition and its type.

Treatment Options

While there is no universal cure, treatment focuses on easing symptoms, preventing complications, and improving quality of life.

medications:

  • Hydroxyurea helps the body produce more healthy red blood cells and reduces pain crises.

  • FDA-approved options include Oxbryta (voxelotor), Endari (L-glutamine), and Adakveo (crizanlizumab).

  • Children may take antibiotics like penicillin to prevent infections.

  • Pain relievers, from over-the-counter drugs to stronger prescriptions, help manage pain.

blood transfusions: Donor blood increases healthy red blood cells, lowers sickle cell counts, and helps prevent complications like stroke.

bone marrow transplant: A potential cure that replaces damaged marrow with healthy donor marrow. This option requires a closely matched donor and carries risks.

gene therapy: Recently approved in the U.S., this involves modifying a patient’s own cells in a lab before returning them to the body. Access is currently limited.

Prevention

Because SCD is inherited, it cannot be prevented after birth. However, genetic testing can help parents understand their risk of passing on the condition. Tests during pregnancy, such as examining amniotic fluid or placenta samples, can determine whether a baby may develop SCD.

lifestyle steps to reduce complications include:

  • Staying hydrated

  • Avoiding extreme temperatures and high altitudes

  • Maintaining vaccinations

  • Following a nutritious diet

  • Exercising regularly

  • Taking prescribed medications

  • Attending regular checkups with a healthcare team

Complications Of Sickle Cell Disease

Sickle-shaped cells can cause long-term damage to organs and tissues.

serious complications include:

  • Acute chest syndrome: Blockage in the lungs causing pain and breathing difficulty.

  • Avascular necrosis: Bone tissue death due to lack of blood supply, often in the hip.

  • Blood clots: Increased risk of deep vein thrombosis (DVT).

  • Kidney and liver problems: Reduced blood flow can lead to organ damage.

  • Pulmonary hypertension: High blood pressure in the lungs, potentially life-threatening.

  • Splenic sequestration: Enlarged spleen from trapped sickled cells.

  • Stroke: Blocked blood vessels reduce oxygen to the brain.

  • Vision loss: Damage to blood vessels in the eye.

Living With Sickle Cell Disease

Living with SCD means managing chronic symptoms and preventing crises.

daily impact: Pain, fatigue, and shortness of breath affect daily activities. Severe cases may cause organ complications and vision problems.

genetic awareness: Not everyone with the sickle cell trait develops the disease, but knowing your genetic risk is important when planning a family.

treatment support: A hematologist can design a care plan with medications, lifestyle guidance, and treatment strategies to help patients live longer, healthier lives.

While there is no widely available cure yet, medical advances—including gene therapy—offer hope for better outcomes in the future.