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Sickle Cell Disease

Reviewed by: Robin E. Miller, MD
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What Is Sickle Cell Disease?

Sickle cell disease is a group of conditions in which red blood cells are not shaped as they should be. Red blood cells normally look like round discs. But in sickle cell disease, they're shaped like sickles, or crescent moons, instead.

The sickle shaped cells cause problems because:

  • They are stiff and sticky and block small blood vessels when they get stuck together. This stops blood from moving as it should, which can lead to pain and organ damage.
  • They break down faster than normal red blood cells. That leads to too few red blood cells, a condition called anemia.

sickle cell

What Are the Signs & Symptoms of Sickle Cell Disease?

The pain caused by sickle cell disease is called a pain crisis or vaso-occlusive crisis. In a pain crisis:

  • Pain may happen in any part of the body.
  • Cold, stress, illness, or dehydration can bring on pain but often there is not an obvious trigger.
  • The pain may last a few hours, a few days, or sometimes longer.

Sometimes pain can be managed at home. But someone with severe pain might need treatment in a hospital.

Signs of anemia include:

  • paleness, often seen in the skin, lips, or nailbeds
  • tiredness
  • dizziness
  • being short of breath
  • feeling lightheaded
  • being irritable
  • trouble paying attention
  • a fast heartbeat

People with sickle cell anemia may have jaundice (skin and whites of the eyes look yellow). This happens because the sickle-shaped red blood cells break down faster than normal cells.

What Problems Can Happen?

People with sickle cell disease can have problems that need care by a doctor right away, such as:

  • Acute chest syndrome: Caused by , infection, and blockages of small blood vessels of the lung. Signs include chest pain, coughing, trouble breathing, and fever.
  • Aplastic crisis: This is when the body temporarily does not make enough red blood cells, and can cause severe anemia. Signs include paleness, extreme tiredness, and a fast heartbeat.
  • Infection: People with sickle cell disease are a risk for some bacterial infections. It's important to watch for fevers of 101°F (38°C) or higher, which can be signs of an infection. Call your doctor and get medical care right away if a fever happens.
  • Priapism: Guys with sickle cell disease can have painful, long-lasting erections. If it's not treated quickly, damage can cause problems with getting erections later in life.
  • Stroke: Sickle-shaped cells can block small blood vessels in the brain, causing a stroke. Signs can include headache, , weakness of the arms and legs, speech problems, a facial droop, or loss of consciousness.

People with sickle cell disease are also at risk for problems such as leg ulcers, bone or joint damage, gallstones, kidney damage, eye damage, and delayed growth.

What Causes Sickle Cell Disease?

Sickle cell disease is a group of conditions passed down in families through their genes. The type of sickle cell disease a person has depends on the hemoglobin genes each parent passes down to them. Hemoglobin is the protein inside red blood cells that carries oxygen. Someone with sickle cell disease has at least one sickle cell gene. The other gene can be either another sickle cell gene or a gene for a different type of abnormal hemoglobin. The genes cause the body to make hemoglobin that causes the red blood cells to become sickle shaped.

Here’s how sickle cell genes can run in families:

  • Someone who gets two sickle cell genes, one from each parent, will have sickle cell disease.
  • Someone who gets a sickle cell gene from one parent and a normal hemoglobin gene from the other parent has . Most people with sickle cell trait don't have symptoms, but they can pass the sickle cell gene to their children.
  • Someone who gets a sickle cell gene from one parent and another kind of abnormal gene from the other parent may have a different form of sickle cell disease, such as hemoglobin SC disease or sickle beta thalassemia.

How Is Sickle Cell Disease Treated?

Stem cell transplant (also called bone marrow transplant) is the only known cure for sickle cell disease. Transplants are complex and risky procedures, and for now are an option only for some patients.

Scientists are studying gene therapy as a possible cure for sickle cell anemia. One day, it's hoped that doctors can stop the disease by changing or replacing the abnormal gene that causes it.

But even without a cure, people with sickle cell disease can lead fairly normal lives if they follow their treatment plan. Their plan might involve:

  • Immunizations and daily doses of penicillin to help prevent infection. Besides having all recommended childhood vaccinations, teens with sickle cell disease should get the pneumococcal, flu, coronavirus (COVID-19), and meningococcal vaccines.
  • Taking folic acid supplements to help them make new red blood cells.
  • Taking hydroxyurea, a medicine that makes sickled red blood cells less sticky. This helps people have fewer painful episodes and other complications. Hydroxyurea needs to be taken every day.
  • Taking L-glutamine, another medicine that is newly approved for sickle cell disease.
  • Taking medicines to help when pain does happen.
  • Getting blood transfusions.

When Should I Call the Doctor?

Someone with sickle cell disease needs medical care right away if any of these problems happen:

  • a fever of 101°F (38°C) or higher
  • pain that isn't getting better with medicine
  • chest pain
  • severe headaches or dizziness
  • severe stomach pain or swelling
  • shortness of breath or trouble breathing
  • extreme tiredness
  • skin that's yellow or very pale
  • an erection that is not going away or is painful
  • sudden change in vision
  • seizures
  • weakness or trouble moving part of the body
  • slurred speech
  • loss of consciousness (passing out)
  • numbness or tingling

What Can Teens With Sickle Cell Disease Do to Feel Better?

To manage sickle cell disease:

  • Go to all doctor's visits and share any concerns or new symptoms.
  • Avoid your pain crisis triggers, such as extreme temperatures or stress.
  • Talk to your doctor about which activities are right for you and which you should avoid.
  • Don't smoke, drink alcohol, or use drugs.
  • Drink lots of liquids and get enough rest.
  • Let an adult know right away if you don't feel well.
Reviewed by: Robin E. Miller, MD
Date reviewed: May 2022