Melanoma typically appears as an unusual mole or spot with uneven color, irregular edges, and an asymmetric shape. It can look dramatically different from one person to the next, though. Some melanomas are dark brown or black with multiple shades swirled together, while others are pink, red, or even skin-colored. Knowing the full range of what melanoma can look like gives you a much better chance of catching it early.
The ABCDE Rule for Spotting Melanoma
Dermatologists use five visual features to distinguish melanoma from ordinary moles. These aren’t pass-fail criteria, but the more of them a spot has, the more suspicious it is.
- Asymmetry. If you drew a line through the middle of the spot, the two halves wouldn’t match. Normal moles are roughly round or oval and look the same on both sides.
- Border irregularity. The edges are ragged, notched, or blurred rather than smooth and well-defined. Pigment may seem to bleed into the surrounding skin.
- Color variation. Instead of one uniform shade, melanoma often has a patchwork of brown, tan, and black. Some areas may include white, gray, red, pink, or blue.
- Diameter. Most melanomas are larger than 6 millimeters across, roughly the size of a pencil eraser. They can be smaller, but growth beyond that threshold is a warning sign.
- Evolving. The spot has changed in size, shape, color, or surface texture over weeks or months. New symptoms like itching, tenderness, or bleeding also count.
A normal mole, by contrast, is usually round or oval with a smooth surface, a distinct edge, and an even color of pink, tan, or brown throughout. It stays stable over time. If one of your moles starts breaking these rules, that’s worth getting checked.
How Normal Moles Differ From Melanoma
Most people have between 10 and 40 common moles, and telling them apart from melanoma comes down to pattern. Your moles generally resemble each other in size, shape, and color. A concept called the “ugly duckling” sign takes advantage of this: if one spot looks noticeably different from all your others, it deserves attention, even if it doesn’t clearly meet every ABCDE criterion.
This works because your body tends to produce moles with a consistent appearance. A dark, irregularly shaped spot surrounded by a dozen small, round, tan moles stands out the way a mismatched bird would in a flock. Studies published in JAMA Dermatology found that this pattern-recognition approach was one of the most effective ways to distinguish melanoma from benign moles, alongside noticing changes over time.
Nodular Melanoma Looks Different
Not all melanomas follow the ABCDE pattern. Nodular melanoma, one of the more aggressive types, grows upward from the skin rather than spreading outward, so it often appears as a firm, dome-shaped bump rather than a flat, irregular patch. It can look like a blood blister.
These growths are usually larger than 1 centimeter across and raised more than 6 millimeters above the skin. They can be brown, black, blue-black, red, pink, or even the same color as your surrounding skin. The surface texture ranges from smooth to crusty to rough, sometimes described as resembling cauliflower. Because nodular melanoma doesn’t always show the classic signs of irregular borders or multiple colors, it’s easy to dismiss as a harmless bump. The key clue is that it’s firm or hard to the touch and appeared recently or is growing quickly.
Pink and Skin-Colored Melanoma
Amelanotic melanoma is a particularly tricky variant because it produces little or no pigment. Instead of the brown-black coloring people associate with skin cancer, these melanomas appear as pink, red, or skin-toned spots. They account for roughly 2 to 8 percent of all melanomas.
In clinical descriptions, these lesions show up as reddish papules or plaques with smooth or slightly shiny surfaces. Some have faint traces of light brown, light blue, or light gray, but never the deep brown or black that would trigger alarm. Because they don’t look like what most people picture when they think “melanoma,” they’re frequently mistaken for pimples, bug bites, or small scars. If you have a pinkish bump that doesn’t heal within a few weeks or keeps slowly growing, it’s worth having a dermatologist look at it.
Melanoma on Palms, Soles, and Nails
Acral lentiginous melanoma develops in places many people don’t think to check: the palms of the hands, the soles of the feet, and under fingernails or toenails. It typically starts as a brown or black discoloration that resembles a bruise or stain, but unlike a bruise, it doesn’t fade. Over time it grows larger.
When melanoma forms under a nail, it’s called subungual melanoma. It usually looks like a dark vertical streak running the length of the nail bed. In about 65 percent of cases, it begins as a single dark band on one nail. Bands wider than 3 millimeters with irregular edges are more concerning, especially if the band is wider near the cuticle than at the tip. A particularly telling sign is called the Hutchinson sign: pigment that spills from the nail onto the surrounding skin of the cuticle or nail fold. As the melanoma progresses, it can cause the nail to crack, break, or lift away from the nail bed. It’s sometimes mistaken for a fungal infection or a bruise from stubbing a toe.
Melanoma on Darker Skin Tones
Melanoma is less common in people with dark skin, but when it does occur, it’s more likely to be diagnosed at a later stage. The most common form in people with darker skin is acral lentiginous melanoma, the type that appears on palms, soles, fingers, toes, and nail beds.
On dark skin, melanoma can look like a dark or black bump that may seem waxy or shiny. On the palm or sole, it may appear as a dark patch. Under a nail, it shows up as a dark band. Because these locations aren’t typically exposed to the sun, people often overlook them during self-checks. Regularly examining the bottoms of your feet, between your toes, your palms, and your nail beds is especially important.
What to Watch For Over Time
One of the strongest clues that a spot could be melanoma is change. A documented case published in JAMA showed a mole on a patient’s back transforming into melanoma over an 11-month period. That’s a relatively short window, which is why paying attention to your skin’s baseline matters.
Changes to watch for include a mole getting larger, developing new colors, becoming raised when it was flat, or developing a new surface texture like scaling or crusting. Symptoms count too: a mole that starts itching, feeling tender, or bleeding is behaving differently than it used to. Even subtle shifts, like a border that used to be sharp becoming blurry, can be meaningful. Monthly self-exams where you look at your entire body, including your scalp, between your toes, and your nail beds, give you the best chance of noticing something early.