The most recognizable signs of melanoma are changes in a mole’s shape, color, size, or texture. But melanoma doesn’t always look like a dark, irregular mole. It can appear as a pink bump, a dark streak under a fingernail, or even develop inside the mouth or eye. Catching it early matters enormously: when melanoma is found before it spreads, the five-year survival rate is above 99%. Once it reaches distant organs, that drops to 35%.
The ABCDE Rule for Suspicious Moles
Most melanomas start as flat, pigmented spots on the skin. The ABCDE framework, developed by the National Cancer Institute and used by the American Academy of Dermatology, gives you five features to watch for:
- Asymmetry: One half of the spot doesn’t match the other. Normal moles are roughly symmetrical.
- Border: The edges are ragged, notched, or blurred rather than smooth. Pigment may appear to spread into surrounding skin.
- Color: The spot contains uneven shades of brown, black, or tan. You might also see patches of white, gray, red, pink, or blue within the same lesion.
- Diameter: Most melanomas are larger than 6 millimeters when diagnosed, roughly the size of a pencil eraser. However, they can be smaller, so size alone isn’t a reliable reason to dismiss a spot.
- Evolving: The spot looks different from how it looked weeks or months ago. Any change in size, shape, color, or texture counts.
Of these five, “evolving” is often the most useful in practice. A mole that has looked the same for years is far less concerning than one that’s recently started changing, even if it doesn’t check every other box.
Signs That Don’t Follow the Usual Pattern
Not all melanomas are dark and irregularly shaped. About 5% of melanomas are amelanotic, meaning they lack the dark pigment most people associate with skin cancer. These appear as pink, red, or skin-colored spots and are easily mistaken for a pimple, scar, or irritated patch of skin. Because they don’t look alarming, amelanotic melanomas tend to be diagnosed at a later stage, according to Memorial Sloan Kettering Cancer Center.
Nodular melanoma is another type that breaks the rules. Instead of growing outward across the skin’s surface, it grows downward, making it more dangerous earlier. Nodular melanomas often appear as raised, firm bumps that are actively increasing in size over weeks. Dermatologists use a separate “EFG” checklist for these: Elevated above the skin surface, Firm to the touch, and Growing progressively. The bump may be dark, but it can also be red or skin-colored.
Melanoma Under Nails, on Palms, and on Soles
Acral lentiginous melanoma develops in places most people never think to check: the palms of the hands, the soles of the feet, and under fingernails or toenails. It’s the most common form of melanoma in people with darker skin tones, partly because other types of melanoma are less frequent in this group.
Under the nail, melanoma typically appears as a dark, lengthwise streak or band of pigment. A key warning sign is called Hutchinson’s sign, where the dark pigment extends from the nail bed outward onto the surrounding skin of the cuticle or nail fold. On palms and soles, it may look like an irregularly shaped dark patch that doesn’t match a bruise or callus. Any new pigmented streak in a nail that wasn’t caused by injury deserves evaluation.
Melanoma in the Eyes
Melanoma can develop inside the eye, most commonly in the layer beneath the white of the eye called the uvea. Early eye melanoma often causes no symptoms at all, which is one reason routine eye exams matter. When symptoms do appear, the Mayo Clinic lists these as the most common:
- Flashes of light or floating specks in your vision
- A growing dark spot on the colored part of the eye (the iris)
- A change in the shape of the pupil
- Blurry or worsening vision in one eye
- Loss of peripheral (side) vision
These symptoms overlap with other, more common eye conditions. But a dark spot on the iris that’s new or growing is particularly worth having examined.
Melanoma in the Mouth, Nose, and Other Hidden Areas
Mucosal melanoma develops on the moist tissue lining body cavities. It’s rare, but its symptoms are easy to dismiss as something minor. In the mouth, signs include a persistent sore that won’t heal, a lump on the tongue, unexplained mouth pain, or bleeding. You might also notice that dentures suddenly don’t fit properly.
In the nasal passages, mucosal melanoma can cause repeated nosebleeds from one nostril, a persistent feeling of blockage, continuous runny nose, or facial pain. In the anorectal area, signs include a lump or mass, pain, rectal bleeding, itching, or new constipation. Because these symptoms mimic common, harmless conditions, mucosal melanoma is frequently caught late.
What “Ugly Duckling” Spots Look Like
Beyond the ABCDE criteria, dermatologists use what’s informally called the “ugly duckling” approach. Most of your moles share a general family resemblance: similar color, size, and shape. A spot that looks noticeably different from all the others on your body is worth attention, even if it doesn’t clearly meet ABCDE criteria. This could be the one dark mole among a group of lighter ones, or a flat spot surrounded by raised ones. The principle is simple: outliers are suspicious.
How to Check Your Own Skin
The Skin Cancer Foundation recommends a head-to-toe self-exam every month. You’ll need a full-length mirror and a hand mirror for hard-to-see areas. The spots people most commonly miss are the scalp (part your hair to check), the spaces between toes, the soles of your feet, the backs of your ears, your genitals, and your lower back.
Start by getting familiar with what’s already there. The goal isn’t to diagnose anything yourself. It’s to notice change. Take photos of any spots you want to track so you have a reliable comparison month to month rather than relying on memory. Pay special attention to any spot that’s new, looks different from its neighbors, or has changed in any of the ABCDE dimensions since your last check.
Why Early Detection Changes the Outcome
Melanoma survival depends almost entirely on how early it’s found. Based on data from the American Cancer Society covering patients diagnosed between 2015 and 2021, localized melanoma (still confined to the original site) has a five-year survival rate above 99%. Once it spreads to nearby lymph nodes, that rate drops to 76%. If it reaches distant organs like the lungs, liver, or brain, survival falls to 35%. The gap between those numbers is the case for monthly self-exams and regular skin checks, especially if you have a history of sunburns, many moles, or a family history of melanoma.