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Sickle cell disease can ask a lot of you and your family. Pain, fatigue, frequent appointments, and uncertainty can make everyday life exhausting. For parents and families learning that a baby or young child has sickle cell, there can be a lot to take in.
Even after years of living with the condition, new questions and challenges can still come up. Wherever you or your family are in that experience, clear information can make the next steps feel a little more manageable.
This article offers an overview of the main types of sickle cell disease, how the condition affects the body, and the treatments and ongoing care that can help.
Sickle cell disease (SCD) is a group of inherited blood disorders involving hemoglobin, the oxygen-carrying protein inside red blood cells.
SCD is a lifelong condition. It’s inherited, meaning it’s passed from biological parents to their children through genes. More than 100,000 people in the United States and about 8 million people worldwide live with sickle cell disease.
Healthy red blood cells are flexible, which helps them travel through blood vessels and carry oxygen to tissues throughout the body.
People with sickle cell disease inherit gene variants that lead to an abnormal form of hemoglobin called hemoglobin S (HbS). Red blood cells containing HbS can become stiff, sticky, and shaped like a crescent or sickle, especially when oxygen levels are low.
Because they’re rigid and sticky, sickled cells can obstruct small blood vessels and reduce circulation. These blockages can cause pain and other complications.
Sickle cell disease can affect people of any race or ethnicity. In the United States, however, more than 90 percent of people living with SCD are non-Hispanic Black or African American, according to the U.S. Centers for Disease Control and Prevention (CDC). SCD occurs in about 1 in 365 Black or African American births.
The type of SCD a person has depends on the hemoglobin genes they inherit from their biological parents. Here are some of the most common types.
Hemoglobin SS is the most common type of SCD and is usually one of the most severe forms. It’s also known as sickle cell anemia.
People with HbSS inherit one gene that makes hemoglobin S from each biological parent. Having two of these genes causes red blood cells to be especially prone to sickling.
In hemoglobin SC (HbSC), a person inherits a gene that makes hemoglobin S from one biological parent and a gene that makes hemoglobin C from the other. Hemoglobin C is another abnormal form of hemoglobin.
HbSC is often less severe than HbSS, but symptoms and complications can vary significantly from person to person.
This type of SCD occurs when a person inherits a hemoglobin S gene from one biological parent and a beta-thalassemia gene variant from the other. Beta-thalassemia affects how the body makes normal beta-globin, an important part of hemoglobin.
There are two main subtypes: HbS beta-zero thalassemia and HbS beta-plus thalassemia. HbS beta-zero usually causes more severe disease, while HbS beta-plus tends to be milder.
A few other types of sickle cell disease are much rarer. These include combinations involving genes that make abnormal hemoglobin D, E, or O.
Sickle cell trait (SCT) means a person inherits one gene that makes hemoglobin S and one gene that makes normal hemoglobin A. Most people with SCT have no symptoms of sickle cell disease, although rare complications can occur.
People with SCT are carriers of the sickle cell gene, meaning they can pass the gene to their biological children. If someone with sickle cell trait has a child with another person who also has sickle cell trait, their child may inherit sickle cell disease.
For this reason, people with sickle cell trait who are planning a pregnancy may want to talk to a genetic counselor beforehand.
Sickle-shaped red blood cells don’t move through blood vessels as easily as healthy red blood cells. When they become lodged in small vessels, they can restrict blood flow and reduce oxygen delivery to nearby tissues.
Sickled red blood cells also break down much faster than healthy red blood cells. Healthy red blood cells typically live for about 90 to 120 days, while sickled cells may last only about 10 to 20 days.
Bone marrow keeps making new red blood cells to replace those that break down. With SCD, the body often can’t keep up, which can lead to anemia and fatigue. Anemia means the body doesn’t have enough healthy red blood cells to carry oxygen effectively.
The pattern and severity of SCD symptoms can differ widely from person to person and may change over time.
Common symptoms include:
People with SCD can have sudden episodes of severe pain, often called pain crises or vaso-occlusive episodes. These episodes happen when sickled red blood cells block blood flow, reducing oxygen delivery to tissues.
Pain can affect areas such as the arms, legs, chest, back, or abdomen and may last for hours or days. Some crises can be managed at home, while others require medical care or hospitalization.
SCD can affect almost every organ in the body. Complications may include kidney disease, heart problems, infections, acute chest syndrome, stroke, and progressive organ damage.
In the United States, sickle cell disease is often identified at birth through routine newborn screening.
Not every country routinely screens newborns for sickle cell disease, but all 50 U.S. states do.
To perform this screening, a healthcare provider collects a few drops of blood from a newborn’s heel. The sample is tested for several health conditions, including SCD. Newborn screening can also identify sickle cell trait.
If the screening result suggests that a baby may have SCD, additional blood testing is used to confirm the diagnosis.
For adults who don’t know their sickle cell status, a blood test can determine which types of hemoglobin the body makes. Genetic testing may be used in some cases if blood test results are unclear or more information is needed.
Managing SCD often means preventing and treating pain episodes and complications, along with monitoring for long-term health problems.
In addition to a primary care provider, people with SCD should see a hematologist, a doctor who specializes in blood disorders.
Some medications can help reduce symptoms and complications of SCD. Hydroxyurea, which is taken daily, can reduce the sickling of red blood cells.
It can lower the chance of pain episodes and acute chest syndrome, improve anemia, and reduce hospitalizations and the need for blood transfusions.
Other medication options include L-glutamine oral powder and crizanlizumab, which are approved for different age groups. Both can reduce pain crises. L-glutamine may also reduce the need for hospitalization.
People with SCD have a greater chance of developing infections, in part because SCD can damage the spleen. Staying up to date on recommended vaccines is especially important for children, because infections such as pneumonia can be life-threatening.
The spleen helps to protect the body against infections. If you’re an adult who has had your spleen removed, your doctor may recommend ongoing antibiotics.
Pain management for sickle cell disease varies depending on how severe and frequent the pain is. Your doctor may recommend over-the-counter medicines such as ibuprofen or acetaminophen for mild to moderate pain, while prescription medicines may be needed for more severe pain.
A blood transfusion gives donated blood through an IV. Red blood cell transfusions can boost the number of red blood cells and provide healthy red blood cells that move more easily through blood vessels.
If you have SCD, you may need:
People who receive repeated transfusions are monitored for complications such as iron overload and reactions to donor blood cells.
Living with sickle cell disease requires ongoing care to manage symptoms and lower the risk of complications. Treatment advances have also created more options for some people with SCD.
Know when to seek emergency care. Severe pain, difficulty breathing, chest pain, sudden weakness or numbness, confusion, seizures, or trouble speaking, seeing, or walking can be signs of a serious complication. Seek emergency medical care or call 911 for these symptoms.
Also called a stem cell transplant, this procedure replaces a person’s blood-forming stem cells with healthy stem cells from a donor without SCD. The donor must be a close enough match to lower the risk of serious complications.
Transplants are used more often in children, particularly those who have had serious SCD complications. Adults may also be considered, although transplants carry more risk for adults and may be an option when medicines aren’t working well enough.
A transplant can cure SCD in some people, but it cannot always correct all SCD-related damage that occurred before treatment. Because transplantation carries serious risks, you and your healthcare team can weigh the potential benefits and risks together.
In 2023, the U.S. Food and Drug Administration (FDA) approved two gene therapies for some people with sickle cell disease and repeated sickle cell crises or events:
These therapies aren’t options for everyone with SCD. Talk with your healthcare provider about whether gene therapy may be appropriate for you.
Even after gene therapy or a bone marrow transplant, a person with SCD can still pass the sickle cell gene to their biological children.
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