You probably have a handful of moles you have known since childhood. Most of the time they stay quietly the same, and you glance past them in the mirror. But every so often, one of them starts to change.
That change is what dermatologists are looking for. The American Academy of Dermatology and the CDC both back a simple home check called the ABCDE rule.
The five letters stand for the warning signs of melanoma, the most serious form of skin cancer. Caught while it is still localized, before it has spread beyond the skin, melanoma has a five-year survival rate of more than 99 percent, according to the American Cancer Society.
The AAD estimates one in five Americans will develop skin cancer at some point in life. That is why learning what to look for is one of the most useful few minutes you can spend on your own health.
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The five letters that spell out a warning
A is for asymmetry. If you imagine folding the mole in half, the two halves of a healthy mole should match. In a melanoma, one half looks unlike the other.
B is for border. A normal mole has a smooth, clean edge. A warning mole has an irregular, scalloped or poorly defined border, in the AAD's wording.
C is for color. A healthy mole is one even shade. A suspicious mole shows more than one color, with patches of tan, brown or black, or spots of white, red or blue mixed in.
D is for diameter. Melanomas are usually larger than a pencil eraser, around six millimeters across, by the time they are diagnosed. Smaller ones do exist, so size alone does not rule a spot out.
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E is for evolving. Any change in size, shape, color or height, or new symptoms such as itching, bleeding or scabbing, is a reason to pay closer attention.
Why the E matters most
Evolution is the letter most people miss. The other four describe what a mole looks like at a single moment. The E asks what it looks like compared with last month, or last year.
That is why a monthly check works. Cleveland Clinic recommends looking over your skin about once a month, ideally after a bath or shower when you are already undressed.
The point is not to memorize every freckle. It is to notice when one spot starts behaving differently from the others around it.
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Dermatologists call that the ugly duckling sign. It is a mole that looks or acts unlike its neighbors on your body. Both the AAD and the American Cancer Society flag it as a reason to get checked, because melanomas often stand out from a person's usual pattern of moles.
When to call a dermatologist
See a board-certified dermatologist if a mole meets any of the ABCDE criteria. The same applies to any spot that looks unlike the rest of your skin, or any mark that is new, changing, itching or bleeding.
Skin cancer does not always start in a mole. Other warning signs include a sore that will not heal, a shiny bump or a rough patch that keeps returning. Check those spots on your next monthly round too.
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This article is made and published by Mie Hermansen, who may have used AI in the preparation.