A melanoma spot typically looks like an unusual mole with uneven color, irregular edges, and an asymmetric shape. It can be brown, black, tan, pink, red, or even skin-colored, and most are larger than 6 millimeters wide (about the size of a pencil eraser). But melanoma doesn’t always follow a single pattern. Understanding the full range of what it can look like, including the less obvious forms, is key to catching it early.
The ABCDE Rule for Spotting Melanoma
The most widely used framework for identifying melanoma is the ABCDE rule, developed to describe the features of early-stage melanoma:
- Asymmetry: One half of the spot doesn’t match the other. A normal mole is usually roughly symmetrical.
- Border: The edges are ragged, notched, or blurred rather than smooth. Pigment may spread into the surrounding skin.
- Color: The spot contains multiple shades. You might see brown, black, and tan together, or areas of white, gray, red, pink, or blue within the same lesion.
- Diameter: Most melanomas are larger than 6 millimeters across, though they can start smaller.
- Evolving: The spot has changed in size, shape, or color over the past few weeks or months. Any mole that looks different than it did before deserves attention.
Not every melanoma will check all five boxes. Some early melanomas only show one or two of these features. The “evolving” criterion is often the most important single clue, because any visible change in a mole is worth having examined.
The Ugly Duckling Sign
Beyond the ABCDE checklist, one of the most practical ways to spot a suspicious mole is the “ugly duckling” sign. Most of your moles tend to look similar to each other. If one mole stands out from all the rest, looking noticeably different in color, size, or shape, that outlier deserves closer inspection. It doesn’t need to meet any specific ABCDE criterion. The fact that it doesn’t match its neighbors is itself a warning sign.
The Most Common Type: Flat and Slowly Spreading
The most frequently diagnosed form of melanoma is superficial spreading melanoma. It starts as a flat or barely raised patch of discolored skin and grows outward horizontally before it grows deeper. This horizontal phase can last months, years, or even decades before the spot is recognized. During that time, it slowly enlarges and develops more irregular color and borders. Because it stays flat for so long, it can be mistaken for a harmless freckle or age spot, especially in its earliest stages.
Raised, Firm, and Fast-Growing Melanoma
Not all melanomas start flat. Nodular melanoma grows as a raised bump that feels firm or solid to the touch. Unlike the slow horizontal spread described above, nodular melanoma tends to grow downward into the skin quickly, making early detection especially important. The “EFG” rule helps identify this type:
- Elevated: The lesion is raised above the skin surface.
- Firm: It feels solid rather than soft when pressed.
- Growing: It increases in size over weeks to months.
Nodular melanomas can be dark brown or black, but they can also appear blue-black, red, or pink. Their dome-shaped profile and rapid growth set them apart from the more common flat, slowly evolving type.
Melanoma That Isn’t Brown or Black
One of the most commonly missed forms is amelanotic melanoma, which lacks the dark pigment most people associate with skin cancer. It appears as a pink, red, or skin-colored spot. Because it doesn’t look like a typical dark mole, it’s often confused with a pimple, scar, or other harmless mark. This means it tends to be diagnosed at a later stage compared to pigmented melanomas. If you have a pink or reddish spot that persists for weeks, doesn’t heal, or slowly grows, it’s worth having a dermatologist look at it.
Melanoma on Palms, Soles, and Under Nails
Melanoma can appear in places you might not think to check. Acral lentiginous melanoma develops on the palms of the hands, the soles of the feet, and on or around the nails. On the palm or sole, it looks like a dark brown or black patch that may resemble a bruise or stain, but it grows in size over time instead of fading.
Under the nails, this type of melanoma (called subungual melanoma) usually shows up as a dark vertical streak running the length of the nail bed. The streak is typically less than 3 millimeters wide initially but widens over time. As it progresses, it can cause the nail to crack or break. One important warning sign is called the Hutchinson sign, where the dark pigment spreads beyond the nail onto the surrounding skin of the fingertip or cuticle. Subungual melanoma is sometimes mistaken for a fungal infection or dried blood under the nail, which can delay diagnosis.
What Melanoma Looks Like on Darker Skin
Melanoma can affect people of all skin tones, but its appearance and typical location differ. In people with darker skin, acral lentiginous melanoma is the most common form. That means melanoma is most likely to show up on the palms, soles, fingers, toes, and nail beds rather than on sun-exposed areas like the back or legs.
On darker skin, melanoma can look like a dark or black bump that appears waxy or shiny. On the palm or sole, it presents as a dark patch. Under a nail, it appears as a dark band. Because skin cancer awareness campaigns have historically focused on lighter skin, and because melanoma on darker skin often develops in locations that aren’t routinely checked, diagnosis can be delayed. Regularly examining your palms, the bottoms of your feet, and your nail beds is important regardless of your skin tone.
What to Watch For Over Time
The single most useful habit for catching melanoma early is knowing what your skin normally looks like. When you’re familiar with your existing moles and marks, you’ll notice when something changes. Pay attention to any spot that grows, changes color, develops an irregular border, starts to itch or bleed, or simply looks different from what you’re used to seeing. Men over 50 have an elevated risk of melanoma compared to the general population, but the disease can develop at any age and on any body type. A full self-check every few months, including hard-to-see areas like your back, scalp, between your toes, and under your nails, gives you the best chance of finding something early, when treatment is most effective.