PHOTO BY THINKSTOCKYou may have heard of the “ABCDE” trick that dermatology experts came up with to help you determine dangerous skin spots: Flag moles that are Asymmetrical, have irregular Borders, contain more than one Color, have a Diameter greater than the size of a pencil eraser, or Evolve and change over time.
This is a good surveillance method, but it isn’t foolproof, says Clifford Perlis, M.D., a dermatologist at the Fox Chase Cancer Center in Philadelphia.
“While many melanomas meet the ABCDE criteria, there are some that don’t,” he says. “And even within it, there are outliers. For instance, many cases of melanoma can be smaller than a pencil eraser.”
(These eye-popping pictures show you exactly What Skin Cancer Looks Like.)
Obviously you should see a dermatologist for an annual skin screening, but you also need to be vigilant on your own. Here’s how to watch out for your own skin.
It Could Be Melanoma If:
It’s new. “After your mid-30s, you shouldn’t be growing new moles,” Dr. Perlis says. See a fresh spot? Point it out to your doctor. Most melanomas arise from previously normal skin, while only 28 percent of cases develop from an existing mole, according to a new study from Harvard Medical School.
Related: Top 10 Cancer Signs You Shouldn’t Ignore
Best case: It’s just a sunspot or liver spot. These small, flat, light brown patches look like moles and tend to pop up on sun-exposed areas like your forearms and shoulders.
They aren’t cancerous, but it’s hard to tell the difference between a simple sunspot and something that might be serious.
