Skin cancer is the most common cancer in the United States, and most people still think the only warning sign is a changing mole. Doctors say that belief leaves a lot of cases undetected.
According to Healthline, two skin cancer specialists outlined a range of signs that patients and doctors routinely overlook. Paul Banwell, an internationally trained plastic surgeon and skin cancer specialist from the United Kingdom, said the most commonly missed sign is straightforward: a sore that will not heal.
"One of the most commonly overlooked signs is a sore or patch of skin that simply doesn't heal after several weeks," Banwell said.
He added that patients should also watch for persistent scaly patches, shiny or pearly bumps, and lesions that repeatedly bleed or crust over. These get dismissed as dry skin, eczema, or minor injuries. That mistake can delay diagnosis by months.
Banwell said mole changes do still matter, but the approach most people use is wrong. Comparing your moles to someone else's is not useful. Instead, he said, the goal is to know your own skin well enough to notice when something shifts. A mole that grows larger, changes shape, develops uneven borders, shifts in color, or starts to itch, bleed, or become tender all warrant a medical evaluation. The single most important factor, he said, is change over time.
Tanya Evans, MD, a board certified dermatologist and medical director of the Skin Cancer Program at the Melanoma Clinic at MemorialCare Saddleback Medical Center in Laguna Hills, described a screening tool that most people have never heard of. It is called the ugly duckling sign.
"A powerful yet underutilized screening tool is the 'ugly duckling' sign," Evans said. "This is a mole that simply looks different from all surrounding moles (nevi), even if it does not meet ABCDE criteria, is an independent predictor of melanoma."
The ABCDE criteria, widely used in dermatology, stands for asymmetry, border, color, diameter, and evolution. Evans is pointing out that a mole can pass all five of those tests and still be worth examining if it simply looks out of place compared to everything around it.
On sun protection, Banwell said the goal is not to avoid sunlight entirely but to be sensible about it. He recommends a broad-spectrum sunscreen with at least SPF 30 every day, stepping up to SPF 50 for extended time outdoors. Sunscreen needs to be applied generously and reapplied every two hours, or more often after swimming or sweating. He also recommends combining sunscreen with shade during the hottest parts of the day and wearing a wide-brimmed hat.
Skin cancer is highly treatable when found early. The consistent message from both specialists is that patients should not wait for something to look like a textbook mole change before seeking evaluation. Any skin change that persists, bleeds repeatedly, or simply looks different from everything else nearby is worth a conversation with a dermatologist.
