Can Skin Rashes Be a Sign of Skin Cancer?
This article explains skin cancer rashes, including common symptoms and causes. It also discusses how to identify skin cancer rashes versus noncancerous rashes and when to call the doctor.
A skin cancer rash can develop from the skin cancer itself. Rashes can also be a side effect of treating local or metastatic skin cancers.
Immunotherapy boosts the immune system to attack abnormal cells. However, it can lead to autoimmune-type rashes. A 2018 review finds that rashes and itchy skin occur in more than one-third of people undergoing cancer treatment.
Radiation therapy for skin cancer will also cause the area to be discolored, scaly, and itchy.
Like other rashes, a skin cancer rash can appear anywhere on the body, including the:
- face or neck
- chest or back
- arms or legs
- mucosal areas, such as the moist lining of the mouth
Symptoms of skin cancer rash vary depending on the cause. A rash can also evolve and look different over the course of skin cancer and treatment.
Symptoms of a skin cancer rash include:
- redness or discoloration
- blotches, or hyperpigmented or hypopigmented patches
- roughness or scaling
- bruising or purple spots (purpura)
- blisters, or welts on the skin or in the mouth
- peeling, cracked skin
- painful or sensitive skin
- burning, stinging, or itchiness
- skin cancer and other cancers, including:
- cancer treatments, such as:
- some medications used in cancer treatment, such as pain medication or hormone treatments
A skin cancer rash can result from:
- the skin cancer itself
- other types of cancer, including:
Cancer treatments that can cause a skin rash include:
- radiation therapy
- targeted therapy
- stem cell transplant
- other medications, such as antibiotics and antimicrobial agents
However, there are many other causes of skin rash that are not related to cancer. Some include:
- infection resulting from bacteria, fungus, or virus
- insect bites
- side effects of medication unrelated to cancer treatment
- skin conditions
Common rashes from cancer treatment include:
- Papulopustular eruption: This rash may occur on the chest, upper back, or face from certain cancer treatment medications.
- Radiation dermatitis: This rash may occur in the area of the skin receiving radiation therapy.
- Radiation recall: This rash may develop on an area of skin that previously had radiation therapy. It can also occur if you have chemotherapy or targeted therapy after completing radiation therapy. Nerve pain and nerve sensations are also possible.
- Hand-foot syndrome: This condition can cause redness, swelling, pain, or tingling in the palms of your hands and soles of your feet.
The symptoms of a skin cancer rash and other rashes are similar. As such, it is challenging to know if your rash is a sign of cancer or something else. Most rashes are benign and will either resolve independently or with a diagnosis and treatment.
Contact your doctor about:
- a skin rash that does not quickly resolve on its own
- a pink scaly patch
- any rash that appears to be growing
- any warning signs of the three main types of skin cancer
Basal cell carcinoma
Signs of basal cell carcinoma include:
- flat, firm, pale, or yellow area that may look like a scar
- reddish patch that is raised and may be itchy
- small pearly bump, which may appear red, pink, shiny, translucent, or have black, brown, or blue areas
- pink growth with raised edges and a depressed center
- regular blood vessels that spread out and resemble spokes of a wheel
- an open sore that may be crusty or ooze, will not heal, or that heals and then returns
Squamous cell carcinoma
Signs of squamous cell carcinoma include:
- rough or scaly red patch that may crust or bleed
- raised lump or growth that may have a lower area in the center
- an open sore that may be crusty or ooze, does not heal, or heals and returns
- wart-like growth
Signs of melanoma include:
- a new spot on the skin or a spot that is changing in size, shape, or color
- a spot that looks different from all of the other spots on your skin
- a spot that has warning signs from the ABCDE rule
ABCDE rule of skin cancer symptoms
- A for asymmetry: With skin cancer, half of the spot may not match the other.
- B for border: The edges, or borders, of skin cancer marks are irregular, scalloped, ragged, or blurred.
- C for color: The color of a skin cancer mark is not uniform and may have different shades.
- D for diameter: The size of a mark is larger than 6 millimeters, or roughly the size of a pea. However, it can sometimes be smaller.
- E for evolving: The appearance may change in size, shape, or color.
In addition to skin cancer, other types of cancer can cause a skin rash. It is rare for rashes to occur due to other cancers. However, these cancers may include:
- mycosis fungoides
- Sézary syndrome
- acute myeloid leukemia
- Kaposi’s sarcoma
Mycosis fungoides is a cutaneous T cell lymphoma, meaning it occurs in T cells (white blood cells) in the skin. The T cells become cancerous, causing different types of skin lesions.
The first sign is often one or multiple red or brown scaly patches of skin. These patches may be slightly indented. The rash begins on the skin that does not often have sun exposure, such as the:
- upper thigh
Sézary syndrome is a more aggressive type of lymphoma. It can present on its own or evolve as an advanced form of mycosis fungoides. It causes a red, itchy rash covering a large area of the body. Other symptoms include:
- thickening skin on palms of hands, soles of feet, or both
- swelling lymph nodes
- losing hair
- thickening fingernails, toenails, or both
- drooping eyelids
- being unable to control body temperature (hypothermia)
Acute myeloid leukemia
Acute myeloid leukemia starts in the bone marrow. It can quickly move into the blood.
Leukemia cells spreading to the skin can cause firm, dark red, purple, or reddish brown lesions on the extremities or torso. Other general symptoms of acute myeloid leukemia include:
Kaposi’s sarcoma develops from cells that line the lymph or blood vessels. It usually appears first as spots on your legs or face. However, it may also appear on other areas of your body. The lesions may be:
- purple, red, or brown
- flat patches
- flat but slightly raised plaques
Other cancer causes of a skin rash
Other cancers that might appear as a rash on the skin include:
- Paget’s disease
- leukemia and other blood-related cancers
- histiocytosis X, or Langerhans cell histiocytosis (LCH)
Internal cancers that can metastasize and present on the skin include:
Acute febrile neutrophilic dermatosis is a rare skin condition. It involves painful skin lesions on the back, arms, neck, and face. Other symptoms include fever and joint inflammation. It can occur with some cancers, including breast cancer.
Other names for this condition include Sweet’s syndrome, neutrophilic dermatosis, and Gomm-Button disease.
Not every skin rash is related to cancer. Many other things that can cause a skin rash, including:
- infection resulting from a bacteria, fungus, or virus
- poison ivy, oak, or sumac
- medication side effects
- skin conditions, such as psoriasis, chickenpox, and eczema
- insect bites
- certain chemicals
- autoimmune diseases
Most rashes are not life threatening. Some may be a sign of infection, allergic reaction, or cancer.
Skin cancer treatment is most successful when doctors diagnose the cancer early. Contact your doctor if you notice:
- no relief from over-the-counter medications
- itching that does not go away after a few days
- scratching until your skin breaks or bleeds
- blisters or crusty skin
- bright red or warm skin
- a rash that is painful, uncomfortable, or keeps you awake at night
- a rash that gets worse after using creams or ointments
- foul-smelling, yellow, or green drainage or pus
- yellowish skin or urine the color of tea
- other symptoms, including diarrhea and fever
Seek emergency care if you have a rash that is:
- spreading rapidly
- all over your body
- accompanied by a fever
People with skin cancer can develop a rash from the disease itself or certain cancer treatments.
Many other things can cause a rash, including other types of cancer, certain conditions, and skin irritants. To identify a skin cancer rash, you can look for other signs of skin cancer. These signs can vary depending on the different skin cancer types.
If you notice any signs of skin cancer or symptoms of a rash, let your doctor or dermatologist know. These signs include redness or discoloration, itching, scaling, bumps, blisters, or welts. If your rash is a sign of skin cancer, early treatment can help prevent it from spreading or coming back.