According to the American Academy of Dermatology, in melanoma checks, "A" is for asymmetry.
"So, typically, a lesion will be symmetrical, if it’s normal," says dermatologist Dr. Juan-Carlos Martinez.
He says an asymmetric lesion can signal trouble.
The "B" in this test is for border.
"So you want to have smooth borders like an even oval shape or an even, circular shape," says Dr. Martinez.
Irregular or scalloped borders can indicate melanoma.
"C" is for color," adds Dr. Martinez. "So, typically, a mole will have one or two colors in it. If you start to see three or more different, distinct colors within a single lesion, that’s something that may warrant biopsy or further inspection."
"D" is for diameter. A lesion larger than 6 millimeters – about the size of a pencil eraser – should be evaluated, especially if it has any of the other features mentioned.
"And 'E' is probably the most important," Dr. Martinez explains.
"E" is for evolving. Is the mole changing over time?
"That may be something that needs to be more carefully evaluated or possibly even biopsied."