What Is It?

Sickle cell is an inherited condition that is passed down from your parents the same way people get the color of their eyes, skin and hair. There is no way to catch sickle cell – it is not contagious.

  • Sickle cell begins with hemoglobin, the part of the red blood cell that carries oxygen. People with sickle cell have a type of hemoglobin that when it releases oxygen, it clumps together on one side of the red blood cell, causing the cell to sickle or become banana-shaped.  
  • Sickle cell affects about 100,000 people in the United States alone. People of African descent make up 90% of the population with sickle cell in the U.S. It also affects people of Hispanic, South Asian, Southern European and Middle Eastern ancestry.

How Do Sickled Cells Affect The Body

  • Sickled red blood cells are stiff and sticky and don’t move freely throughout the blood vessels.
  • Sickled red blood cells can pile up and block blood flow like a traffic jam, keeping healthy red blood cells carrying oxygen from getting where they need to go. This may prevent your organs from getting the oxygen they need.
  • Because sickled red blood cells break down, there are fewer and fewer in the body to carry oxygen. When there are too few red blood cells carrying oxygen, anemia can result, which causes people to feel weak and tired.

How Does Sickle Cell Disease Change Over Time?

The process of hemoglobin clumping together to form a long chain inside the red blood cells is called polymerization. This chain of hemoglobin is what causes the red blood cells to change into a sickled shape. When red blood cells sickle, they can’t do their job of carrying oxygen throughout the body as well. When this process begins, it creates room for the following components to take place in the body:

  • Vaso-occlusive crisis (VOC) or pain crisis, which is the blockage of blood vessels
  • Hemolysis, which is the breakdown or bursting of red blood cells
  • Anemia, which is having too few red blood cells
  • Endothelial dysfunction, which occurs when the thin layer of cells doesn’t work the way it should and causes blood vessels to constrict or narrow
  • Inflammation, which is damage resulting from sickle cell that leads to an increased inflammatory response in the body.

It is unknown how much each of these components of sickle cell may impact your overall health.

Sickle cell disease changes over time, impacting your overall health. The long-term impact of sickle cell can occur 24 hours a day, 7 days a week and 365 days a year, even when pain is not felt.

It’s important to note that whether you experience day-to-day symptoms or not, the overall impact of the disease is progressive and damage can still be occurring in your body. This is why it’s important to learn about your disease early and work with your healthcare team to develop healthy, preventative habits at a young age.


Join the Conversation

© 2023 Pfizer Inc.
All rights reserved.
November 2023.

This website is intended for U.S. residents.

The information provided is for educational purposes only and is not intended to replace discussions with a healthcare provider.