Approximately, two in three Australians will be diagnosed with skin cancer by the time they are 70, according to the Cancer Council. The good news? Skin cancers, including melanomas (the most deadly kind of skin cancer), are typically curable if they're found and removed early. That's why it's important to not only see a dermatologist for an annual skin exam, but to also give yourself a head-to-toe examination every month.

But what exactly should you be looking for? Basal cell and squamous cell carcinomas (the most common types of skin cancer) might be itchy, bleeding, waxy, patchy, or shiny. The signs of melanoma are a bit different, though. To identify potentially worrisome moles you'll want to use the ABCDE system.

<em>This basal cell carcinoma has a waxy scar-like area as well as on open, crusty sore.</em>

ABCDE stands for "asymmetrical," "border," "colour," "diameter" and "evolving," which are the characteristics that can differentiate benign moles from cancerous ones. Examples of each of these characteristics are illustrated in the photos below. The images are a little graphic, but familiarising yourself with the signs of melanoma could potentially save your life.

⚠️ If you spot scaling, redness, or a change in a mole's size, shape, or color, call your doctor ⚠️

asymmetry mole

Asymmetrical moles

The healthy mole (left) has symmetrical borders-meaning if you drew a line through the middle of the mole, its left and right halves would be more or less the same, surgeon Dr Erica Friedman says. Compare that to the asymmetrical melanoma on the right. “It would be near impossible to draw a line through this sucker and get equal halves,” Dr Friedman says. The different colours and the irregular border of this mole are also indicative of skin cancer, he says.

Irregular Border mole

Irregular Border moles

While the healthy mole (left) has a fairly consistent border-at least as far as mole borders go-the mole on the right has no real perimeter, Dr Friedman notes. “The lesion is haphazardly arrayed on the skin, the border is not congruent nor well defined, and there is a mix of colors,” he says, explaining the mole’s worrisome features.

loss of Color mole

Uneven Colour moles

Again, starting with the healthy mole at left, notice the consistent color pattern. While there’s a slightly lighter halo on the skin around the mole, the mole itself is all the same shade of brown. While the other cancerous moles shown above have revealed how the color of a cancerous mole can be spotty or inconsistent, Dr Friedman says a lack of colour is also a red flag. (See the mole at right.) “Most assume that melanoma has to be jet black, but a loss of colour can be equally as damning,” he says.

mole with large diameter

Large Diameter

If the mole or spot is larger than a pea, that’s another indication of skin cancer. The mole on the right is larger than a pea, and so fits the “D” criteria, Dr Friedman says. The inconsistent border and colour-especially that pink/white portion in the middle-left section of the mole-are also telltale signs of cancer, he says.

skin cancer pictures

Ugly ducklings

Along with the ABCDEs, Friedman also recommends looking closely at “ugly duckling” moles or spots. These are the oddballs, he says, or those moles that look different from all the others. You’re bound to have some randos that don’t look like all their mole brothers and sisters. So don’t freak out. But you’ll want to keep an eye on these to watch for changes, as well as the other symptoms outlined above. When in doubt, see a specialist, Dr Friedman says.

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