Sickle cell anemia is an inherited blood disorder that changes the shape of red blood cells, making them stick together and block blood vessels

In sickle cell anemia, a genetic mutation causes hemoglobin—the protein that carries oxygen in red blood cells—to form differently. Instead of staying round and flexible, red blood cells become rigid and curved like a sickle or crescent moon. These misshapen cells get stuck in small blood vessels, cutting off blood flow and oxygen to tissues. This blockage causes pain, organ damage, and a shortage of healthy red blood cells, which is why the condition is classified as a form of anemia.

The disease is inherited, meaning you must receive the sickle cell gene from both parents to have sickle cell anemia. If you inherit the gene from only one parent, you carry the sickle cell trait but typically do not have the disease itself. Sickle cell anemia occurs most often in people of African descent, but it also appears in people from the Mediterranean, Middle East, and Latin America.

Key Takeaways

  • Sickle cell anemia is caused by a genetic mutation that makes red blood cells rigid and crescent-shaped instead of round and flexible.
  • The misshapen cells block blood vessels, causing pain crises, organ damage, and a chronic shortage of healthy red blood cells.
  • You must inherit the sickle cell gene from both parents to have the disease; inheriting it from one parent means you carry the trait but usually do not have the disease.
  • Symptoms typically begin in early childhood and include pain episodes, fatigue, shortness of breath, and swelling in the hands and feet.
  • Treatment focuses on managing pain, preventing complications, and in some cases using medications or blood transfusions to increase healthy red blood cells.

How sickle cells damage your body

When sickle cells block blood vessels, they starve tissues of oxygen. This causes acute pain crises—sudden, severe pain that can last hours or days and may require hospitalization. Pain most often strikes in the bones, chest, abdomen, and joints, though it can occur anywhere in the body.

Over time, repeated blockages damage organs. The spleen, which filters blood and fights infection, is often damaged first and may stop working by early adulthood. Damage to the lungs can cause acute chest syndrome, a life-threatening condition with chest pain, fever, and difficulty breathing. The kidneys, liver, heart, and bones can all be harmed by chronic oxygen deprivation. Some people develop stroke risk because sickle cells can block blood vessels in the brain.

The constant destruction of sickle cells also creates chronic anemia. Normal red blood cells live about 120 days; sickle cells survive only 10 to 20 days. Your bone marrow cannot replace them fast enough, leaving you with fewer healthy cells to carry oxygen. This causes fatigue, shortness of breath, and pale or yellowish skin.

Symptoms that appear in childhood

Sickle cell anemia symptoms usually emerge between 5 and 6 months of age, though some children show signs earlier. Newborn screening programs in all U.S. states test for sickle cell disease, so most cases are caught before symptoms develop.

Early signs include swelling and pain in the hands and feet (called hand-foot syndrome), persistent fatigue, shortness of breath, and yellowing of the skin and eyes from the breakdown of red blood cells. As children grow, pain crises become more frequent and severe. Some children have frequent infections because a damaged spleen cannot fight bacteria effectively. Growth may be delayed, and puberty may come later than in peers without the disease.

Symptoms vary widely. Some people have mild disease with few pain crises; others experience severe, frequent episodes that disrupt school, work, and daily life. The unpredictability of pain crises is itself a major challenge—a person may go weeks without symptoms, then have multiple crises in a short period.

Genetic inheritance and testing

Sickle cell anemia follows an autosomal recessive inheritance pattern. This means both parents must carry the sickle cell gene for a child to have the disease. If both parents carry the gene, there is a 25 percent chance with each pregnancy that the child will have sickle cell anemia, a 50 percent chance the child will carry the trait, and a 25 percent chance the child will inherit neither.

Carriers of the sickle cell trait usually have no symptoms and live normal lifespans. However, they can pass the gene to their children. Genetic counseling can help families understand their risk if both parents are carriers or if there is a family history of sickle cell disease.

Testing for sickle cell disease or trait involves a blood test that looks at hemoglobin structure. Newborn screening catches most cases in infancy. Adults can be tested if they have symptoms, a family history, or want to know their carrier status before having children.

Treatment approaches and pain management

There is no cure for sickle cell anemia except in rare cases where a bone marrow or stem cell transplant succeeds, which carries significant risks and is typically only an option for children with a matched sibling donor. Most treatment focuses on managing pain, preventing complications, and increasing the number of healthy red blood cells.

Hydroxyurea is a medication that reduces the frequency and severity of pain crises by increasing fetal hemoglobin, a type of hemoglobin that does not sickle. It also lowers the risk of acute chest syndrome and organ damage. Other newer medications work by different mechanisms to prevent sickling or reduce vaso-occlusive crises.

During a pain crisis, treatment includes strong pain medication, fluids given intravenously to prevent dehydration, and oxygen if blood oxygen levels are low. Blood transfusions may be used to increase the number of healthy red blood cells and reduce sickling. Some people receive regular transfusions to prevent stroke or manage severe complications.

Daily care includes staying hydrated, avoiding triggers like cold, stress, and high altitude, taking folic acid supplements to support red blood cell production, and getting vaccinations to prevent infections. Many people with sickle cell anemia work with a hematologist (blood specialist) who coordinates their care.

Living with sickle cell anemia

Sickle cell anemia is a lifelong condition that requires ongoing medical care and self-management. Life expectancy has improved significantly over the past few decades—many people now live into their 50s or beyond—but the disease still shortens lifespan and affects quality of life.

Pain crises are unpredictable and can interfere with school, work, and relationships. Some people experience depression or anxiety related to chronic pain and the burden of managing a serious illness. Mental health support, pain management specialists, and support groups can help. Many workplaces and schools can make accommodations, such as flexible schedules or access to rest areas during pain episodes.

Pregnancy carries additional risks for women with sickle cell anemia, including increased pain crises, blood clots, and complications for the fetus. Preconception counseling with a maternal-fetal medicine specialist is important for family planning.

When to seek medical care

Seek immediate medical attention for severe chest pain, difficulty breathing, sudden weakness or numbness, severe headache, or loss of consciousness—these can signal life-threatening complications like acute chest syndrome or stroke. Also seek urgent care for a pain crisis that does not improve with home treatment, fever above 101.5°F, or severe swelling and pain in the hands or feet.

Regular appointments with a hematologist help monitor organ function, adjust medications, and catch complications early. People with sickle cell anemia should have a primary care doctor who understands the disease and can coordinate care with specialists.

Frequently Asked Questions

Is sickle cell anemia the same as sickle cell trait?

No. Sickle cell anemia is the disease—you inherit the sickle cell gene from both parents and have symptoms. Sickle cell trait means you inherited the gene from one parent only; you usually have no symptoms and live a normal lifespan, but you can pass the gene to your children.

Can sickle cell anemia be cured?

A bone marrow or stem cell transplant can cure it, but this is only an option for a small number of people, usually children with a matched sibling donor, because the risks are significant. Most people manage the disease with medication, pain management, and preventive care.

What triggers a pain crisis?

Common triggers include dehydration, cold exposure, stress, infection, high altitude, and strenuous exercise. Triggers vary from person to person. Staying hydrated and avoiding known triggers helps reduce crisis frequency.

Can people with sickle cell anemia have children?

Yes, but pregnancy carries higher risks of pain crises and complications. Women with sickle cell anemia should work with a maternal-fetal medicine specialist before and during pregnancy to monitor their health and the baby's development.

How is sickle cell anemia diagnosed in newborns?

All U.S. states screen newborns for sickle cell disease using a blood test from a heel prick, usually done within 24 to 48 hours of birth. If screening is positive, a follow-up test confirms the diagnosis so treatment can begin early.