What Is Cold Agglutinin Disease?

Medically Reviewed by Melinda Ratini, MS, DO on March 01, 2024
4 min read

Cold agglutinin disease (CAD) is a condition that makes your body’s immune system attack your red blood cells and destroy them. It’s triggered by cold temperatures, and it can cause problems that range from dizziness to heart failure. It’s also called cold antibody hemolytic anemia.

About 1 person in 300,000 gets cold agglutinin disease. It shows up most often in people over 60, and women are more likely to get it than men.

When you breathe in, your red blood cells carry oxygen from your lungs to the rest of your body. Then they carry carbon dioxide back to the lungs for you to breathe out. A typical red blood cell lives about 120 days.

Your body’s immune system makes proteins called antibodies that help you fight off infections. Some of these antibodies are called cold agglutinins because they’re triggered when your body’s temperature is below normal.

With CAD, those antibodies attach themselves to red blood cells instead of to bacteria or viruses and eventually kill the red blood cells. When they do that faster than your body can replace red blood cells, it leads to a condition called anemia, which is when your body doesn’t have enough red blood cells. 

CAD can make you feel weak and tired. Other signs of it include:

  • Dizziness and headaches
  • Sore back, legs, or joints
  • Ringing in your ears
  • Irritability or changes in your behavior
  • Pale or yellow skin
  • Vomiting or diarrhea
  • Cold feet or hands
  • Chest pains or an irregular heartbeat 

In women, cold agglutinin disease sometimes keeps them from having periods.

Some people who have cold agglutinin disease also may get a cold, numb feeling, and loss of color in their fingers or toes, known as Raynaud’s phenomenon.

Symptoms are typically worse in the winter when temperatures are lower.

Most of the time, cold agglutinin disease happens by itself, without any other related health problem. Doctors call that the primary, or idiopathic, form of the condition, and they don’t know why it happens.

In other cases, another illness can bring on cold agglutinin disease. One of the most common conditions that triggers it is lymphoma, especially in people over 60. That's a type of cancer that affects your lymph nodes. But it also can happen if you have:

  • A bacterial infection like E. coli, syphilis, or Legionnaire’s disease
  • A virus, like the ones that cause the flu, hepatitis C, or AIDS
  • A parasitic infection like malaria
  • Other conditions that cause your immune system to turn on your body
  • Other kinds of cancer that affect your blood cells, like multiple myeloma or leukemia

If your doctor thinks you have cold agglutinin disease, blood tests can tell. A nurse or lab technician will take a sample of your blood so it can be looked at under a microscope.

  • A complete blood count checks for signs of anemia, like lower numbers of red blood cells and a larger-than-normal number of new red blood cells.
  • Your doctor will also want to see if the red blood cells are clumping together, which is another sign of the illness. 
  • If a complete blood count shows signs of CAD, another kind of blood test will look for a higher-than-normal number of cold agglutinins, the antibodies that kill red blood cells. This is called a direct antiglobulin test or a Coombs test.

Your doctor may also feel your midsection to see if your liver or spleen is larger than it should be.

This depends on how serious your symptoms are and whether CAD happened on its own or because of another illness.

If you have another condition that’s led to CAD, your doctor will try to treat that first and see if it helps your symptoms. For example, if it was brought on by bacteria or a virus, your symptoms may go away a few months after you get over the infection.

If your symptoms are mild, you may not need treatment. You may be able to avoid problems by keeping warm and staying out of cold weather.

If your red blood cell count is very low, your doctor may need to filter your blood to get rid of the antibodies that are causing your condition (a procedure called plasmapheresis) or give you a blood transfusion. These are short-term treatments that can give you temporary relief, but they don’t do anything about the cause of the problem.

If your anemia is severe, you may need to take medication. The only drug approved to specifically treat CAD is sutimlimab-jome (Enjaymo). It works by inhibiting the destruction of red blood cells and so decreases the need for blood transfusions.

Another drug commonly used for CAD is rituximab, a drug that targets certain immune cells. (It was originally made to treat lymphoma.) You’ll probably get a dose once a week for several weeks.

If these treatments don’t work, your doctor might suggest a drug called bortezomib that was made to treat a kind of cancer called multiple myeloma.

Living with CAD starts with keeping warm. That means bundling up in winter and sometimes even in summer, since air-conditioning can sometimes trigger a reaction. You may want to bring extra clothing or find comfortable undergarments you can wear on a regular basis.

You might need to stay away from cold foods and drinks as well.

Cold agglutinin disease is a rare condition, but if you have it, you’re not alone. Support organizations and online communities can help you learn more and connect with others who are going through the same things.