Anything that increases your risk of getting a disease is called a risk factor. Having a risk factor does not mean that you will get cancer. Likewise, not having risk factors doesn't mean that you will not get cancer. People who think they may be at risk should discuss this with their doctor. Risk factors for Merkel cell carcinoma include the following:
Being exposed to a lot of natural sunlight
Being exposed to artificial sunlight, such as from tanning beds or psoralen and ultraviolet A (PUVA) therapy for psoriasis
Having an immune system weakened by disease, such as chronic lymphocytic leukemia or HIV infection
Taking drugs that make the immune system less active
History of Cancer
Being male or white or over the age of 50
Signs and Symptoms
Merkel cell carcinoma usually appears on sun-exposed skin as a single lump that is fast-growing, painless, firm and dome-shaped (or raised) and red or violet in color.
A doctor should be consulted immediately if changes to the skin are seen.