This page was reviewed under our medical and editorial policy by
Maurie Markman, MD, President, Medicine & Science
This page was updated on June 1, 2022.
Skin cancer is the most common type of cancer in the United States. Below are some common questions and answers about the basics of the disease, its symptoms, prevention and risk factors.
What causes skin cancer?
As with many cancers, skin cancer develops when damaged cells grow uncontrollably. Most skin cell damage is caused by exposure to ultraviolet (UV) radiation from the sun or tanning beds. Cells may also be damaged by inherited DNA mutations or cell replication errors, or they may develop in patients whose immune system is suppressed, such as those who received an organ transplant or were infected with the HIV virus.
Is melanoma considered skin cancer?
Yes. Melanoma is a rare but very aggressive form of skin cancer. Melanoma accounts for about 2 percent of all skin cancers, but it is responsible for most skin cancer deaths. The disease develops in the melanocytes, or the cells that lie just below the skin surface and give skin its color. Like most skin cancers, exposure to UV radiation is a major risk factor in terms of what causes melanoma. But unlike most skin cancers, melanoma may develop on parts of the body not normally exposed to the sun, such as the groin, armpits or bottoms of the feet. Melanoma also is more prone to travel (metastasize) than most skin cancers. When metastatic melanoma occurs, melanoma cells most often travel to the lungs, liver, bone and brains. Surgeries required to remove melanoma from the skin are typically more invasive and involve wider and deeper incisions than procedures to remove other skin cancers, such as basal cell or squamous carcinomas. Removing nearby lymph nodes may also be necessary to determine whether the cancer has spread.
What are the other different types of skin cancer?
The primary types of skin cancer are:
Basal cell carcinomas: This is the most common form of skin cancer, accounting for nearly 80 percent of all cases, according to the American Cancer Society. These cancers occur in the cells just below the skin's surface.
Squamous cell carcinomas: This form of skin cancer accounts for about 20 percent of all cases. Squamous cells are also found in the throat, the lining of the digestive system and respiratory tract and major organs like the liver and kidneys.
Merkel cell carcinomas: Though very rare, this cancer is an aggressive form of skin cancer. Merkel cells, sometimes called touch cells because they give the skin its ability to sense touch, are found below the epidermis, nestled next to nerve endings.
Kaposi's sarcoma (KS): This type of skin cancer may appear as purplish blotches or lesions on the skin (usually on the face or legs), but it may also form inside the mouth or in lymph nodes. In rare cases, lesions may develop in the lungs, causing breathing problems.
Lymphoma of the skin: Lymphoma, which is cancer of the lymphatic system, may form in a variety of locations in the body, including the spleen, lymph nodes, thymus and skin. This cancer may appear as red or purple patches, moles or pimples on the skin that may itch or ulcerate. Other symptoms may include fatigue and weight loss.
Learn more about diagnosing skin cancer
What are the signs and symptoms of skin cancer?
Skin cancer usually begins as a simple, painless spot, sore or rash on the skin. If that sore or rash doesn’t heal, or if the spot changes color or becomes irregular in shape, it may be skin cancer. Basal cell carcinomas on the head or neck may appear as a pale patch of skin or a waxy bump. On the chest, it may look more like a brownish scar or flesh-colored lesion. These spots may bleed or ooze and become crusty in some areas. Squamous cell carcinomas may also develop as a lump on the skin. But, unlike the smooth and pearly appearance of a basal cell carcinoma, these lumps may be rough on the surface. The cancer may also form a reddish, scaly patch. Merkel cell carcinoma may appear as a fast-growing, dome-shaped lump on the skin. These bumps are usually painless and may be red or purple. Melanoma may appear as a dark spot on the skin. It may change shape and color and bleed as it develops. It may be difficult to tell if a growth on the skin is a mole, a benign growth or skin cancer. That’s why experts recommend that suspicious or fast-growing spots be checked by a doctor.
How can I tell if my skin cancer is melanoma?
The ABCDE method may help you determine if an abnormal growth on your skin may be melanoma:
Asymmetry: The mole has an irregular shape.
Border: The edge is not smooth, but irregular or notched.
Color: The mole has uneven shading or dark spots.
Diameter: The spot is larger than the size of a pencil eraser.
Evolving or Elevation: The spot is changing in size, shape or texture.
The only way to be sure if a mole is melanoma is to have it examined by a doctor.
Learn more about melanoma risk factors
Treatment for skin cancer often varies depending on the type, location, stage and/or other factors. Below are answers to some common questions about available treatments for skin cancer and melanoma:
What are my skin cancer treatment options?
Treatments for skin cancer vary widely depending on the cells affected and the stage of the disease. Most basal cell or squamous cell carcinomas may be treated in an outpatient procedure by a dermatologist. The affected area may be removed with a local excision or by cryotherapy, which uses a very cold a substance such as liquid nitrogen to freeze and destroy the cancer cells. More advanced basal cell or squamous cell cancers may require more extensive surgeries and treatments. Surgery to treat melanoma and Merkel cell carcinomas may require a wide excision and the removal of lymph nodes. Chemotherapy, radiation, targeted therapy and immunotherapy are all treatment options for melanoma and Merkel cell carcinoma.
Learn more about treatment options for melanoma
What side effects can I expect from my treatment?
Depending on the location and extent of the surgery required to remove the cancer, reconstructive or plastic surgery may be an option to repair damaged tissue. Surgical procedures for skin cancer may be painful. Surgery to remove lymph nodes may result in swelling, caused by the buildup of lymphatic fluid, a condition known as lymphedema. Chemotherapy, targeted therapy and immunotherapy drugs may cause a variety of side effects, such as nausea and vomiting, fatigue, nerve damage, mouth sores and rashes. Patients who undergo radiation therapy may experience skin irritation.
What types of doctors will I see during my treatment for skin cancer or melanoma?
Depending on your type and stage of skin cancer, your care team may include a number of physicians, including one or all of the doctors below:
You may have many questions about treatment options for skin cancer and melanoma. Getting answers from your doctor may help you make more informed decisions about your treatment plan. Below are some important questions skin cancer patients should ask their doctors:
What does it mean that my cancer has metastasized?
Metastasis occurs when cancer cells break off from the primary tumor, spread elsewhere and establish new tumors in other parts of the body. Basal cell carcinomas and squamous cell carcinomas, which account for more than 95 percent of all skin cancers, rarely metastasize. Melanoma, however, is among several cancers that may travel, or metastasize, to other parts of the body. In most cases, metastatic melanoma spreads to the brain, lungs, bones and/or lymph nodes. Metastatic skin cancer may require extensive surgery, chemotherapy and other treatments. You may also consider talking to your doctor about therapies that may help you manage symptoms and side effects. Metastatic cancer is different than recurrent cancer, which is cancer that returns to the same part of the body.
Is immunotherapy an option for me?
Immunotherapy drugs called checkpoint inhibitors have been approved to treat certain types of melanoma and Merkel cell carcinoma. These drugs work by disrupting chemical signals that cancer cells send to help hide from the immune system. The U.S. Federal Drug Administration has approved the checkpoint inhibitor drugs pembrolizumab (Keytruda®), ipilimumab (Yervoy®) and nivolumab (Opdivo®) to treat melanoma. The checkpoint inhibitor avelumab (Bavencio®) has been approved to treat advanced Merkel cell carcinoma. Immunotherapies, though, are not recommended for all patients, so talk to your oncologist about whether you are a candidate for these drugs.
Should I participate in a clinical trial?
Cancer treatments have improved tremendously over the years, thanks to advances made possible because of patients who have participated in studies exploring new treatment options, drug protocols or other approaches before they were granted federal approval. These clinical trials may offer participants new treatment options that may have otherwise been unavailable to them, especially after exhausting conventional treatments. If you are interested in participating in a clinical trial, ask your doctor whether you qualify, and discuss any concerns or questions you may have, to help you determine whether it’s a good fit for you.
How can I reduce my risk of getting skin cancer?
Exposure to UV radiation is the primary cause of cell damage that may lead to skin cancer. One important way to reduce your risk of skin cancer is to avoid sun exposure when possible and/or protect yourself from damaging rays. Consider following these tips:
What is ultraviolet radiation?
UV radiation is among several types of light emitted by the sun. It's also a carcinogen. Most of the UV light that reaches the earth is UVA, the long-wave ultraviolet rays that penetrate the skin more deeply than UVB (shortwave) rays. These strong rays can reach the skin’s deepest layers, where melanocytes (skin cells that determine the skin’s color) are located. Melanocytes absorb UVA, producing the pigment melanin, which darkens the skin. But too much UVA may damage melanocytes, potentially causing melanoma. UVB rays are not nearly as prevalent or potent, but they may burn the outer layers of skin.
How do I examine myself for skin cancer?
Take the time once a month to examine your body, literally from head to toe. It helps if you have a large or full-length mirror and a hand-held mirror. Starting with the top of your head, look for new spots, irregular or raised spots or spots that have changed or grown since your last exam. Use the hand-held mirror to look behind your ears, the back of your neck and top of your scalp. Ask a partner or spouse to look at your back, the backs of your knees or other places that are hard to see. Don't forget to check the soles of your feet and between your fingers and toes. Consider using a body map to keep a record of suspicious spots, and bring it to the doctor during your annual physical.
Next topic: What are the preventative measures for skin cancer?