Leukemia Rashes: Why These Skin Lesions Occur and What They Look Like

"Leukemia rash" describes a range of skin symptoms that can come from leukemia, a type of blood cancer that starts in the bone marrow. Some people might notice tiny red spots on their arms or legs, while others may find their hair follicles are itchy and painful. Leukemia rashes can also occur as a result of some treatments, like chemotherapy.

With that said, people get rashes for many reasons, and most of the time they're not leukemia rashes. If you apply a new moisturizer that contains an irritating ingredient, touch poison ivy, or are recovering from a virus, you might very well end up with a rash. Even stress can cause a rash. In rare cases, however, a rash may be a sign of a handful of types of cancer—leukemia being one of them, as Moffitt Cancer Center points out.

Still, most people with leukemia don't get a rash, Felipe Samaniego, MD, professor in the Department of Lymphoma/Myeloma, Division of Cancer Medicine at the University of Texas MD Anderson Cancer Center, tells Health. Other leukemia symptoms, like bruising easily and spiking a fever for no clear reason, are far more common. But leukemia rashes do occasionally crop up in people with this type of cancer.

Here's what to look for and why a leukemia rash can occur.

What does a leukemia rash look like?

Leukemia rashes can vary in appearance, depending on what's causing them. The disease itself can cause a leukemia rash, says MD Anderson Cancer Center, but so can some cancer treatments and other infections.

A leukemia rash might look like:

• petechiae, which are tiny, pinprick-sized dots that are usually red or brown
• tender nodules that are red, gray, or bluish in color
• nodules or lesions that are violet-colored

People often wonder where a leukemia rash appears, and the truth is that it can crop up anywhere on your body, including your arms, legs, torso, face, or neck, per the National Organization for Rare Disorders (NORD). That's just one of many reasons why other skin issues can be confused for a leukemia rash, even when you don't have cancer.

Leukemia rash pictures

When leukemia cells enter the skin, asymptomatic lesions can appear, says DermNet NZ. The rashes that people develop can vary widely in their appearance, from tiny spots to large nodules.

These images depict a couple of ways that leukemia rashes can present.

Why does leukemia cause a rash?

The cause of leukemia rashes isn't always clear, but it can be one manifestation of the disease, says Dr. Samaniego. The most likely explanation for a leukemia rash ties back to the underlying problem in this type of blood cancer, which is an overproduction of abnormal white blood cells.

Often this abundance of white cells impedes the bone marrow's ability to make enough red blood cells and platelets (the latter of which are essential for normal blood clotting), says the American Society of Hematology.

If your platelet count is low, you may bleed and bruise more easily, and broken capillaries under your skin can cause petechiae, says Moffitt Cancer Center. The tiny red or brown spots from petechiae aren't technically a rash, but they can look like one.

Someone might also get a leukemia rash if the cancer has spread to their skin (leukemia cutis), explains the American Cancer Society. In that case, a grouping of cancer cells might form visible lumps under the skin. It can also cause patches of the skin to become discolored.

In other instances, someone can develop a leukemia rash if they have already been diagnosed with leukemia and are being treated with a granulocyte-colony stimulating factor drug. Per NORD, that medication can lead to a reaction called Sweet syndrome, which can cause a rash of tender red and bluish-red bumps or lesions to develop suddenly on the body.

Leukemia rash treatments

Treatment for a leukemia rash will depend on what your doctor thinks is causing it. If you haven't been diagnosed with leukemia and aren't sure what's causing a mysterious rash, consult a dermatologist.

If you have leukemia and you're taking a granulocyte-colony stimulating factor drug, your doctor might stop that medication (as it can lead to a leukemia rash) and also prescribe a corticosteroid to reduce the inflammation.

If the leukemia rash is a result of cancer cells themselves having spread to the skin, the best fix is to treat the cancer itself (often with chemotherapy, immunotherapy, or targeted therapy, notes the Cleveland Clinic). "You treat the cancer and the rash goes away," says Dr. Samaniego.

Is a rash a sign of leukemia?

Most of the time, rashes have nothing to do with leukemia. If you have a skin condition that looks like a leukemia rash and don't know why, there's no reason to assume it means you have cancer—especially if you don't have any other leukemia symptoms. That said, you shouldn't ignore it: See a doctor anytime a rash is coupled with other health problems (fever, sore throat, joint pain, etc.) or if it stems from a tick bite.

You should also get a rash checked out if it's all over your body, very painful, looks infected, or doesn't clear up within two days. And of course, you should seek medical attention ASAP (call 911) if you have a rash as well as swelling of your lips or tongue, vomiting, or trouble breathing; these could be signs of a life-threatening allergic reaction, cautions the Cleveland Clinic.

If you have reason to believe you have a leukemia rash, talk to your primary care doctor. A simple blood test can likely help your doctor decide if leukemia is a possibility and if other tests or a referral to an oncologist is in order. If you've been diagnosed with blood cancer and develop a leukemia rash, tell your oncologist right away. Your treatment regimen might need to be tweaked.

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