The ABCDEs of Melanoma: A Self-Check You Can Do Tonight
Five letters dermatologists use to tell a harmless mole from a dangerous one, so you know exactly what to look for the next time a spot worries you.
The ABCDE rule (Asymmetry, Border, Color, Diameter greater than 6mm, and Evolving) is the dermatologist-standard checklist for catching melanoma early, the stage at which the 5-year survival rate exceeds 90 percent.
The American Cancer Society notes that the most important warning sign of melanoma is any new spot, or any spot that is changing in size, shape, or color, while the Skin Cancer Foundation emphasizes that 'E' for Evolving was added precisely because change over time is such a strong predictor.
Questions we get a lot
What do the letters in ABCDE actually stand for?
A is Asymmetry (one half doesn't match the other), B is an irregular or poorly defined Border, C is Color that varies within the spot, D is Diameter larger than about 6mm (a pencil eraser), and E is Evolving, meaning the spot is changing over time. Dermatologists use these as a quick triage tool, not a diagnosis. Any spot that hits one or more of these is worth showing a professional.
Why was 'E' for Evolving added to the original ABCD rule?
The Skin Cancer Foundation explains that 'E' was added because change over time, in size, shape, color, or symptoms like itching or bleeding, is one of the strongest warning signs of melanoma. A spot that looks stable for years but suddenly starts changing should be evaluated. Evolving captures melanomas that might otherwise look small or unremarkable in a single snapshot.
Can a melanoma be smaller than 6mm?
Yes. The American Cancer Society cautions that some melanomas are smaller than the 6mm guideline, so diameter is a rule of thumb rather than a hard cutoff. This is also why the 'ugly duckling' sign, a spot that simply looks different from your other moles, is useful. When in doubt, have a dermatologist check it rather than relying on size alone.
r/SkincareAddiction: 'I have a mole that's been the same my whole life but suddenly looks darker on one side, is that something I should panic about?'