What Is Sickle Cell Crisis?

A Complication of Sickle Cell Disease

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Sickle cell crisis is a health complication of sickle cell disease, an inherited blood disorder. It usually causes severe pain, and it happens due to an acute blood cell reaction. Sometimes sickle cell crisis is triggered by physical stress, such as an infection, and it can also happen without a trigger.

Painful episodes are treated with pain medication. Medication is also available to help prevent sickle cell crisis. Some people who have sickle cell disease experience frequent crises, and some people with the condition rarely experience them. 

Man experiencing shortness of breath

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Types of Sickle Cell Crisis 

There are several conditions that are defined as sickle cell crisis, and they can cause sudden, severe, and sometimes dangerous effects. 

The major common types of sickle cell crisis are:

  • Vaso occlusive pain: This type is considered the most common. It occurs when the red blood cells form a sickle shape and block small blood vessels. This can cause extreme pain in the affected areas of the body. 
  • Acute chest syndrome: This type can occur when the small blood vessels of the lungs become blocked by sickle-shaped red blood cells. It can cause shortness of breath, low oxygen levels, and it can be fatal. 
  • Aplastic crisis: This condition occurs when the bone marrow slows or stops making red blood cells, leading to severe anemia (low numbers of healthy red blood cells). 
  • Splenic sequestration: This occurs when the red blood cells accumulate in the spleen. It causes enlargement of the spleen and severe anemia. 
  • End organ damage: The sickled cells can accumulate in the blood vessels of any organ, causing pain and organ damage. Examples include priapism (prolonged penile erection), intestinal ischemia (damage to the intestine due to lack of blood flow), and stroke (blockage of blood flow in the brain). 

Sickle cell disease has other health effects that are not considered sickle cell crisis, including anemia, a predisposition to infection, a risk of serious complications such as kidney and liver damage, and avascular necrosis (a type of joint damage).

Symptoms and Complications

Sickle cell crisis can cause a variety of symptoms. These are related to the organ that is affected.

Symptoms can include:

  • Pain can affect the muscles, bones, and joints in the extremities, chest, or back. 
  • Shortness of breath occurs due to acute chest syndrome. 
  • Generalized weakness, low blood pressure, pain, or a change in consciousness can occur when organs are affected. 
  • Severe weakness or loss of consciousness can occur due to aplastic anemia.

These symptoms can develop over the course of hours or days. You can have more than one type of sickle cell crisis at a time.

A sickle cell crisis can cause lasting damage to the body, which can worsen with more frequent episodes.

Causes and Triggers 

There are several situations that can trigger a sickle cell crisis. For people who have sickle cell anemia, these changes can make the red blood cells prone to forming a sickle shape, and may also cause changes in small blood vessels, making it harder for blood to flow smoothly.

Sickle-shaped red blood cells are not smooth like healthy red blood cells. Instead, they become sticky and prone to clumping together and blocking blood vessels anywhere in the body.  

Triggers for a sickle cell crisis include:

  • Infections 
  • Dehydration (loss of body fluids without adequate replacement)
  • Cold temperature
  • Stress 
  • Surgery or medical illness 
  • Low oxygen 


If you have sickle cell disease, you can also experience a crisis without a trigger, and you might not have a crisis every time you experience a trigger.

Can You Prevent Sickle Cell Crisis? 

Sickle cell crisis can cause substantial distress, and it takes at least a few days to resolve. Sometimes a sickle cell crisis can be dangerous. Preventive therapies can help reduce the severity and frequency of sickle cell crises for people who have sickle cell disease. 

Prevention includes medical interventions and lifestyle approaches. Medical interventions that treat sickle cell anemia may reduce the frequency of crises and include hydroxyurea, L-glutamine, chronic blood transfusion, and stem cell transplant (replacing the blood-forming cells in the bone marrow).

Oxbryta (voxelotor), a drug that prevents the red cells from sickling, has received accelerated approval by the Food and Drug Administration (FDA) for clinical use in people ages 4 and up.

Other potential treatments are being investigated in research trials, including anti-inflammatory treatments, Dacogen (decitabine) and tetrahydrouridine (increase hemoglobin in the blood), and gene therapy (replacing defective genes in stem cells).

Lifestyle approaches for preventing sickle cell crisis include: 

  • Stay hydrated, especially after exercise, during an infection, or during any medical illness.
  • Reduce the risk of infections with methods such as frequent handwashing, avoiding close contact with people who you know have an infection, and staying up to date on recommended vaccinations
  • Maintain stable temperatures by wearing gloves, hats, and other temperature appropriate clothes as needed.
  • Exercise in moderation. 
  • Avoid high altitudes, where there is low oxygen.

If you have sickle cell disease, there is no way to completely assure that you will never have a sickle cell crisis, but lowering your risk is beneficial for your health.

What Are the Treatments for Sickle Cell Crisis? 

In general, sickle cell crisis is managed symptomatically. Most of the time, pain medication is prescribed.

If you are able to experience pain relief with over-the-counter (OTC) medication, your healthcare provider will let you know how much you can safely take. Some powerful prescription medications that are commonly used to treat a sickle cell crisis, such as morphine, can have severe side effects, including profound constipation.

Pain control is important, and your healthcare providers will give you prescription-strength oral or intravenous medication to reduce your pain if OTC pain medications are not sufficient.

Other treatments that you might need include: 

  • Intravenous (IV, within a vein) fluids 
  • Supplemental oxygen 
  • Blood transfusion 

If you need to be admitted to the hospital for your treatment, your condition would be monitored closely, and your treatment would be adjusted as needed. 


Sickle cell crisis is a complication of sickle cell disease. There are several types of sickle cell crisis, and they occur when the sickled blood cells accumulate in small blood vessels. An episode can cause severe pain, shortness of breath, or organ damage.

Preventative strategies that involve avoiding avoid risk factors—like infections, cold, dehydration, and stress—can help reduce the risk of sickle cell crises, but they may still occur. Medication is also available to prevent sickle cell crisis. Treatment may include pain medication, blood transfusion, or oxygen supplementation. 

A Word From Verywell

If you or a loved one has sickle cell disease, having a crisis can be painful and it can be harmful to your health. The more you learn about your condition, the better you can help control the factors that may lead to a sickle cell crisis.

Talk to your healthcare provider about a plan so you will know what to do if you begin to experience early symptoms of a sickle cell crisis. Consider joining a support group to meet with other people who are going through the same situation as you. You may be able to encourage each other and to help each other with practical tips. 

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  4. Thuptimdang W, Shah P, Khaleel M, Sunwoo J, Veluswamy S, Kato RM, Coates TD, Khoo MCK. Vasoconstriction response to mental stress in sickle cell disease: The role of the cardiac and vascular baroreflexes. Front Physiol. 2021 Nov 4;12:698209. doi:10.3389/fphys.2021.698209

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By Heidi Moawad, MD
Heidi Moawad is a neurologist and expert in the field of brain health and neurological disorders. Dr. Moawad regularly writes and edits health and career content for medical books and publications.