The ABCDE's of Skin Cancer's Warning Signs

​​​​​​Taking a few simple steps every month to protect your skin could help you avoid becoming one of the more than three million Americans who will be diagnosed with skin cancer this year.

"Skin cancer is the most common form of cancer, but it's also one of the more preventable," says Philip Leming, MD, an oncologist and hematologist with The Christ Hospital Physicians.

How the sun can damage your skin

Ultraviolet (UVA and UVB) radiation from the sun causes premature aging, suppresses the body's immune system and increases the risk for skin cancer.

UVA and UVB rays are responsible for three common forms of skin cancer:

  • Basal cell carcinoma. This type of skin cancer appears as lesions that look like red patches, open sores or scars. Basal cell carcinoma accounts for about 80 percent of all skin cancers. It is linked to sun exposure and is highly treatable when detected early.
  • Squamous cell carcinoma. This is the second most common form, representing about 20 percent of all skin cancers. It often appears as a sore, red patch or wart. Squamous cell carcinoma is also linked to sun exposure and highly treatable when detected early.
  • Melanoma. Although melanoma represents a small percentage of skin cancers, it's the most deadly since it can spread to other organs. These growths vary greatly in appearance and can sometimes resemble normal moles. Melanoma is closely tied to sun damage (sunburns) early in life and tanning bed use. In fact, a recent study reports that melanoma rates are rising in women under the age of 40, and tanning beds could be to blame.

Practice sun-safe behaviors

The good news is most skin cancers can be avoided by practicing sun-safe behaviors, including:

  • Avoiding tanning beds. If you must have a tan, get it from a bronzer or lotion.
  • Avoiding the sun between 10 a.m. and 4 p.m. This is when UV rays are strongest.
  • Always wearing broad-spectrum sunscreen of SPF 30 or higher. Apply about 2 tablespoons to your entire body 30 minutes prior to sun exposure and again after activities like swimming or other sports.
  • Wearing UV-blocking accessories or clothing. Wear UV-blocking sunglasses, long sleeves, long pants and wide-brimmed hats whenever you can.
  • Being aware of your own skin. Perform monthly skin exams and yearly skin cancer screenings.

Recognize skin cancer's warning signs

Knowing the "ABCDEs" of skin cancer will help you recognize the signs and symptoms of the disease in its early stages when it's most treatable.

"We sometimes become blind to our own skin because it's something we look at every day," Dr. Leming says. "The simple message is to really look for changes in your own skin, and have a dermatologist do the same."

Check your skin once a month for the following:

  • Asymmetry. Normal moles or freckles look symmetrical on the top and bottom and from side to side.
  • Border. The borders of your moles should be smooth and free of notched, jagged or blurred borders.
  • Color. Each individual mole should have a consistent light or brown color throughout. Black, blue or red moles may also indicate a problem.
  • Diameter. Moles should be smaller than 6 mm, which is about the size of a pencil eraser.
  • Elevation. The surface of your moles should be even with the surrounding surface of your skin.

If you notice any irregularities, make an appointment with your primary care physician who can do a more thorough screening and refer you to a dermatologist if necessary.

"Melanoma, for example, doesn't often have these warning signs," Dr. Leming says. "That's why it's important for people to get skin screenings regularly." 

Learn ​
more about melanoma and the services we offer. ​

Dr. Leming is board-certified in internal medicine, hematology and medical oncology at The Christ Hospital Physicians.