What Is a Leukemia Rash?

Rashes are a common skin reaction to any number of things. Although rare, a rash may indicate leukemia, a type of blood cancer. Leukemia can cause a variety of rashes for different reasons. Leukemia rashes may be tiny dots, big plaques, or itchy bumps. Treatments for leukemia can also cause rashes.

What Is a Leukemia Rash?

Leukemia is a type of blood cancer that changes how bone marrow functions. Bone marrow is where the body makes different cells, such as:

• White blood cells, which fend off bacteria, viruses, and other threats
• Red blood cells, which take oxygen from your lungs to your organs and tissues
• Platelets, which slow down and stop bleeding through clots

With leukemia, genetic mutations cause bone marrow to make too many of one blood cell type, usually white blood cells. Those excess cells do not work correctly. The abnormal cells crowd out healthy cells, which causes symptoms like bruising, unintentional weight loss, and skin rashes.

Although most people with leukemia do not develop rashes, they can happen, Felipe Samaniego, MD, a professor in the department of lymphoma/myeloma at the University of Texas MD Anderson Cancer Center, told Health. 

Types of Leukemia Rash

Leukemia causes many types of rashes, such as:

• Petechiae: Leukemia may cause problems with normal blood clotting, causing bleeding below the skin. Petechiae are little red dots that appear on light skin when tiny blood vessels, called capillaries, bleed under the skin. Petechiae can appear as dark red dots on dark skin.
• Sweet syndrome: Leukemia may cause a sudden high fever and a rash of tender lesions, known as sweet syndrome. Granulocyte-colony stimulating factor drug, a medication that treats leukemia, may also cause sweet syndrome. Sweet syndrome may appear as a reddish-blue rash on light skin or black or brown on dark skin.
  
• Leukemia cutis: This condition develops when white blood cells leave the blood or bone marrow and infiltrate the skin. Leukemia cutis causes plaques, ulcers, blisters, or discolored lesions. Most people diagnosed with leukemia cutis are already diagnosed with leukemia.
• Blastic plasmacytoid dendritic cell neoplasm (BPDCN): This type of leukemia typically presents as skin lesions similar to bruises. BPDCN might look like raised pimples or swellings, ranging from a few millimeters to several centimeters.
• Infections: Both leukemia and its treatments can weaken the immune system. A weak immune system can cause frequent skin infections that cause swelling, pain, redness, pus, and itching.
• Treatment rashes: Leukemia treatments—including chemotherapy, targeted therapy, and immunotherapy—may cause rashes. Rashes can appear on multiple body parts (e.g., scalp, neck, upper body). Symptoms include itching, burning, stinging, or pain.

Leukemia Rash Symptoms

Leukemia rash symptoms depend on what causes the rash. Generally, leukemia rashes cause symptoms such as:

• Skin discoloration
• Bruises
• Raised patches of skin
• Itchiness
• Pain
• Swelling
• Skin flakiness
• Easy bleeding
• Skin that's hot to the touch
• Pus, or a red streak around the rash

What Causes Leukemia Rashes?

With leukemia, the abnormal cells that grow out of control can migrate to other body parts, like the skin. Cancer cells can cause rashes when they spread.

Leukemia and its treatments can weaken the immune system, making it hard for the body to fight harmful bacteria, viruses, and fungi. Skin infections commonly occur among people with leukemia and cause rashes. Treatments can cause adverse reactions, including rashes, as well.

How Is Leukemia Rash Diagnosed?

Consult a healthcare provider if you have symptoms of a leukemia rash. A healthcare provider can perform a physical exam and discuss your personal and family history. They can refer you to a specialist if they cannot diagnose the source of your rash.

A healthcare provider will likely refer you for some tests if you have a rash and other symptoms of leukemia or another blood cancer. Tests commonly include blood tests and imaging.

See a healthcare provider right away if you notice any of the following:

• The rash has spread all over your body, especially if it spreads quickly.
• The rash hurts.
• The rash has turned to blisters.
• The rash is swollen and warm to the touch.
• The rash becomes infected. 
• There is a red streak around the rash.
• You're having trouble breathing.
• You have a fever.

Treatments for Leukemia Rash

Treatment for a leukemia rash depends on the cause. For example, a healthcare provider may advise the following if a leukemia rash results from treatments:

• Changing your treatments or medications
• Applying mild soaps, lotions, or moisturizers
• Taking oral or topical medications
• Using extra skin protection (e.g., wearing sunscreen and loose-fitting clothing)

A healthcare provider will likely directly treat the cause if a leukemia rash results from cancer cells spreading to the skin. Treatments may include chemotherapy, immunotherapy, radiation therapy, or a combination of methods.

How To Prevent Leukemia Rash

There is no one way to prevent leukemia rashes. Many causes of leukemia rashes are unpredictable reactions to the cancer or its treatments. Still, you might be able to help prevent some rashes.

Some ways you can prevent treatment-related rashes include:

• Keep your skin clean with warm water, gentle soap, and soft towels.
• Keep your skin dry, especially if it oozes after a treatment.
• Do not scratch itchy skin.
• Stay out of the sun as much as possible, and wear sunscreen with an SPF of 30 or higher daily.
• Moisturize your skin with a healthcare provider-recommended moisturizer.
• Protect your skin with soft, comfortable clothing that is not too tight.
• Apply topical medications as prescribed.
  

A Quick Review

A leukemia rash may develop due to the cancer spreading to the skin or in response to treatments. Leukemia rashes are rare, and most rashes do not result from leukemia. Consult a healthcare provider if you have an unexplained rash. Tests like blood tests and imaging can determine if leukemia is possible.

Notify a healthcare provider right away if you have leukemia or another type of blood cancer and develop a rash. They may need to update your treatment regimen.