Skin changes, especially rashes, are one of the most common side effects of many cancer treatments. These changes can affect skin anywhere on your body, including your scalp. Skin changes and rashes may also be called cutaneous or dermatologic reactions.
There may be treatments available, depending on your symptoms and what is causing them.
What causes rashes and skin changes?
There are many reasons you might have rashes or other skin changes during cancer and cancer treatment.
Cancer treatments
Cancer treatments are the most common cause of rashes and skin changes in people with cancer. Most types of cancer treatment (including chemo, targeted drug therapy, immunotherapy, radiation therapy, stem cell transplant, and hormone therapy) can cause skin changes.
Medications
Many other types of medications used as part of cancer treatment (such as ones for pain, nausea and vomiting, or diarrhea) can cause skin changes.
It's important to know that if a skin rash is an expected side effect of a certain treatment, it is not considered an allergy or allergic reaction. However, people can have allergies to chemotherapy, immunotherapy, and targeted drug therapy, just like with any other medicine.
Talk to your doctor or cancer care team about your symptoms. They can help you understand what type of reaction you might be having.
Certain cancers
Rashes and skin changes can also be caused by certain cancers. For example, itchiness and night sweats can be symptoms of some lymphomas. Some leukemias and breast cancers can cause rashes.
Other health problems
Other health conditions not related to cancer can also cause rashes or skin changes, such as psoriasis or cellulitis.
Common rashes caused by cancer treatment
Rashes can be a side effect of certain types of chemotherapy, targeted drug therapy, immunotherapy, radiation therapy, or stem cell (bone marrow) transplants.
These are some of the most common rashes caused by cancer treatment:
Maculopapular
Maculopapular rashes have both flat and raised areas. They often look like pink-red bumps on light skin tones and purple-brown bumps on dark skin tones. Maculopapular rashes most often happen on the face, chest, stomach, and back, but they can develop on any area. Some are itchy or uncomfortable.
Papulopustular
Papulopustular rashes usually happen on the chest, upper back, or face. They may be itchy and painful. This is the most common skin rash associated with a type of targeted drug therapy called EGFR inhibitors. As many as 9 out of 10 people get papulopustular rashes as a side effect of EGFR inhibitors.
Acneiform
Acneiform rashes have papules or pustules (small, red bumps with or without pus). They usually happen on the face, scalp, upper chest, or back, and are often described as acne-like bumps.
Erythema multiforme
Erythema multiforme rashes often have raised, round spots known as target lesions because they look like a bullseye target. They usually have three rings with a small blister in the center. This type of rash most commonly affects the hands, feet, and face, but it can develop anywhere. It often appears pink-red on lighter skin tones and red-purple on darker skin tones.
Purpura
Purpura rashes aren’t directly caused by cancer treatment. They are tiny, flat, pin-point spots caused by broken blood vessels close to the skin surface. Low platelets (thrombocytopenia) are the most common reason for purpuric rashes.
Hand-foot syndrome
Hand-foot syndrome is a type of rash that causes redness, swelling, and pain or sensitivity on the palms of your hands or soles of your feet. Targeted drug therapy is the most common cause of this rash in people with cancer. The medical name for hand-foot syndrome is palmar-plantar erythrodysesthesia syndrome.
Steven-Johnson syndrome and toxic epidermal necrolysis
Steven-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare but very severe skin conditions most often caused by medications. Flu-like symptoms such as fever, muscle or joint pain, cough, or sore throat are common, followed by a painful rash.
The rash often starts near the upper body and spreads to other areas such as the face, arms, or legs. Skin often blisters and peels off in large sheets. SJS and TEN can also affect your mucous membranes (areas such as the mouth, throat, colon, or genitals).