The Basic Problem: Misshapen Red Blood Cells

Sickle cell anemia is a blood disorder where red blood cells become rigid and curved—shaped like a sickle or crescent moon—instead of staying soft and round. This happens because of a change in the hemoglobin protein that carries oxygen through your blood. When hemoglobin is abnormal, it sticks to itself inside the cell, forcing the cell into that rigid shape. These stiff cells get stuck in blood vessels, blocking blood flow and causing pain, organ damage, and a shortage of healthy red blood cells in your body.

You are born with sickle cell anemia, not developing it later. It is inherited—you get it only if both your mother and father pass you the gene for sickle hemoglobin. If you inherit the gene from only one parent, you have sickle cell trait, which usually causes no symptoms but means you carry the gene and could pass it to your children.

Key Takeaways

  • Sickle cell anemia is caused by abnormal hemoglobin that makes red blood cells rigid and crescent-shaped, blocking blood vessels and reducing oxygen delivery.
  • The condition is inherited only when both parents pass the sickle hemoglobin gene, making it most common in people of African, Mediterranean, and Middle Eastern descent.
  • Pain crises, organ damage, and chronic anemia are the main complications, though severity varies widely from person to person.
  • Treatment options now include medications that reduce sickling, blood transfusions, and in some cases bone marrow transplant, which can cure the disease.
  • Newborn screening catches sickle cell anemia at birth in all U.S. states, allowing early treatment to prevent serious complications.

How the Sickling Process Damages Your Body

When sickle cells block blood vessels, the tissue beyond that blockage does not get enough oxygen. This causes acute pain crises—sudden, severe pain in bones, joints, chest, or abdomen that can last hours or days. Over time, repeated blockages scar organs. The spleen, which filters blood and fights infection, is often damaged first. The lungs, kidneys, and bones can all be harmed by years of reduced blood flow.

Because sickle cells die faster than normal red blood cells—living 10 to 20 days instead of 120 days—your body cannot replace them quickly enough. This leads to chronic anemia, meaning you always have fewer healthy red blood cells than you need. Chronic anemia causes fatigue, shortness of breath, and delayed growth in children. Some people also develop acute chest syndrome, a life-threatening complication where sickling occurs in the lungs, causing chest pain, fever, and difficulty breathing.

Who Gets Sickle Cell Anemia and Why

Sickle cell anemia is most common in people whose ancestors came from sub-Saharan Africa, but it also occurs in people from the Mediterranean region, the Middle East, and parts of India. In the United States, roughly 1 in 365 Black infants are born with sickle cell anemia, and about 1 in 16,300 Hispanic infants. The gene is more common in these populations because it originally offered some protection against malaria in regions where malaria was widespread.

The inheritance pattern is straightforward: if both parents carry the sickle hemoglobin gene, each child has a 25 percent chance of having sickle cell anemia, a 50 percent chance of having sickle cell trait, and a 25 percent chance of inheriting two normal hemoglobin genes. Genetic counseling before or during pregnancy can help families understand their risk.

Symptoms and When They Appear

Newborns with sickle cell anemia usually show no symptoms at birth because fetal hemoglobin—a different type of hemoglobin present before birth—protects them. Symptoms typically begin between 3 and 6 months of age as fetal hemoglobin decreases and sickle hemoglobin takes over. The first sign is often swelling and pain in the hands or feet, called hand-foot syndrome.

As children grow, symptoms may include pain crises, fatigue, jaundice (yellowing of skin and eyes from the breakdown of old red blood cells), delayed growth, and frequent infections from spleen damage. Severity varies enormously—some people have only a few pain crises per year, while others have many. Some people live into their 50s or beyond; others face life-threatening complications in childhood. This unpredictability makes sickle cell anemia difficult to manage and why close medical follow-up matters.

How Doctors Diagnose Sickle Cell Anemia

Newborn screening catches sickle cell anemia before symptoms start. All U.S. states screen newborns for sickle cell disease using a blood test from a heel prick done within the first few days of life. The test identifies abnormal hemoglobin and alerts doctors to start treatment early, which prevents many serious complications.

In older children or adults, diagnosis begins with a blood smear—a slide of blood viewed under a microscope where sickle-shaped cells are visible—and hemoglobin electrophoresis, a test that separates different types of hemoglobin and shows which type is present. Genetic testing can confirm the diagnosis and identify which specific sickle gene mutation a person has. If you have a family history of sickle cell anemia, your doctor may recommend testing even if you have no symptoms.

Current Treatment Options

Treatment focuses on preventing pain crises, managing complications, and in some cases curing the disease. Hydroxyurea is a medication that increases fetal hemoglobin production, reducing sickling and pain crises by 50 percent or more in many people. L-glutamine is another medication that reduces the frequency of pain crises. Both are taken by mouth daily.

For severe cases, blood transfusions replace sickle cells with healthy ones, reducing pain and preventing organ damage, though repeated transfusions carry risks including iron buildup and immune reactions. Bone marrow transplant (also called hematopoietic stem cell transplant) can cure sickle cell anemia by replacing the faulty bone marrow with healthy marrow from a matched donor, usually a sibling. Success rates are highest in children with matched siblings, though transplant carries its own serious risks. Newer gene therapy approaches are being studied and show promise in early trials.

Living With Sickle Cell Anemia

People with sickle cell anemia benefit from regular care with a hematologist—a doctor who specializes in blood disorders—and preventive measures. Staying hydrated, avoiding extreme temperatures, managing stress, and getting vaccinated against infections all reduce pain crises. Folic acid supplements support red blood cell production. Penicillin or other antibiotics are often given to children to prevent serious infections from spleen damage.

Pain management during crises may include strong opioid medications, fluids, and oxygen. Mental health support is important because chronic pain and the unpredictability of the disease take an emotional toll. Many people with sickle cell anemia work, go to school, and live full lives, though the disease requires ongoing medical attention and lifestyle adjustments.

Frequently Asked Questions

Can sickle cell trait turn into sickle cell anemia?

No. Sickle cell trait is a permanent genetic condition, but it does not progress into sickle cell anemia. People with trait carry one sickle gene and one normal gene, and this does not change. However, if two people with trait have children together, their children have a 25 percent chance of having sickle cell anemia.

Is sickle cell anemia contagious?

No. Sickle cell anemia is an inherited genetic condition, not an infection. You cannot catch it from another person or spread it to others. You are born with it because of genes inherited from both parents.

Can sickle cell anemia be cured?

Bone marrow transplant can cure sickle cell anemia, but it works best in children with a matched sibling donor and carries serious risks including rejection and infection. Gene therapy is showing promise in clinical trials. For most people, treatment focuses on managing symptoms and preventing complications rather than curing the disease.

What triggers a pain crisis?

Pain crises can be triggered by dehydration, infection, cold exposure, stress, or physical exertion, though sometimes they occur without an obvious trigger. Avoiding known triggers and staying hydrated help reduce how often they happen.

Do all people with sickle cell anemia have the same severity?

No. Severity varies widely. Some people have mild disease with few symptoms, while others have frequent pain crises and serious organ damage. Genetic factors and other health conditions influence how severe the disease is for each person.