Melanoma typically appears as an unusual mole or spot with uneven color, irregular borders, and an asymmetric shape. But not all melanomas look the same. Some are dark brown or black, others are pink or red, and some hide under fingernails or on the soles of your feet. Knowing the full range of what melanoma can look like gives you a real advantage in 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 disease. Each letter flags a specific visual warning sign:
- Asymmetry: One half of the spot doesn’t match the other. A normal mole is generally round or oval and roughly symmetrical.
- Border irregularity: The edges look ragged, notched, or blurred rather than smooth. Pigment may seem to bleed into the surrounding skin.
- Color variation: Instead of one uniform shade, you see a mix of brown, tan, black, or even patches of white, gray, red, pink, or blue within the same spot.
- Diameter: Most melanomas are larger than 6 millimeters across (about the size of a pencil eraser) by the time they’re noticed, though they can be smaller.
- Evolving: The spot has changed in size, shape, or color over the past few weeks or months. Any mole that looks different from how it looked before deserves attention.
These criteria work well for the most common type of melanoma, but they don’t catch every form. Some melanomas are small, symmetrical, or lack dark pigment entirely.
The Ugly Duckling Sign
Sometimes the most useful clue isn’t what a single mole looks like, but how it compares to the moles around it. The “ugly duckling” sign refers to any spot that simply looks different from all the others on your body. Most people’s moles share a family resemblance: similar color, similar size, similar shape. A mole that stands out as the odd one deserves closer inspection.
Research published in JAMA Dermatology found this approach has roughly 90% sensitivity for detecting melanoma, meaning it correctly flagged 9 out of 10 confirmed cases. Even people without medical training identified the same outlier lesions that expert dermatologists did. If one mole on your back looks nothing like its neighbors, that contrast itself is a meaningful signal.
Superficial Spreading Melanoma
About 70% of all melanomas are the superficial spreading type, according to Memorial Sloan Kettering Cancer Center. This is the form most people picture when they think of melanoma: a flat or slightly raised spot with uneven borders and mixed colors, often some combination of brown, black, tan, and sometimes pink or blue-gray areas.
It starts growing outward along the top layer of skin before eventually pushing deeper. This horizontal growth phase can last months to years, which is why regular skin checks matter. The average horizontal growth rate for melanomas overall is about 5.3 square millimeters per year, roughly the size of a small lentil added each year. That slow spread gives you a window to notice changes if you’re paying attention.
Nodular Melanoma
Nodular melanoma is the type most likely to catch people off guard. Instead of spreading outward first, it grows downward into the skin from the start, appearing as a raised, dome-shaped bump. It can be dark brown or black, but it can also be pink or skin-colored. It tends to feel firm to the touch.
The standard ABCDE criteria often miss nodular melanoma because these lesions can be small (under 6 mm), round, and symmetrical. A separate set of warning signs, called EFG, was developed specifically for this type: Elevated above the skin surface, Firm when pressed, and Growing progressively over weeks. Patients frequently describe noticing a new bump that simply keeps getting bigger. If you develop a firm, raised spot that wasn’t there before and it doesn’t go away within a few weeks, it’s worth having examined.
Melanoma That Isn’t Dark
One of the most dangerous misconceptions about melanoma is that it’s always brown or black. Amelanotic melanoma produces little to no pigment, so it can appear pink, red, or even close to your natural skin tone. It sometimes looks like a small, persistent sore or a pinkish bump.
This lack of pigment makes it significantly harder to recognize. In one study, clinicians included melanoma in their initial list of possible diagnoses only 32% of the time when the lesion was red or pink, compared to 94% of the time for pigmented melanomas. Red amelanotic melanomas were mistaken for everything from basal cell carcinoma to eczema to bug bites. Because the ABCDE rule focuses heavily on color changes in pigmented spots, it doesn’t reliably flag these lesions. A pink or reddish spot that persists, bleeds easily, or grows steadily should not be dismissed just because it doesn’t look like a typical dark mole.
Melanoma on the Face and Sun-Damaged Skin
Lentigo maligna is a type of melanoma that develops on skin with years of cumulative sun exposure, most often on the face. About 86% of cases appear on the head and neck, with the cheek being the most common location. It looks like a flat, irregularly shaped brown patch, sometimes resembling an age spot or freckle that has slowly expanded.
The coloring ranges from light brown to black, often with uneven shading across the patch. Borders tend to be poorly defined, and as the spot grows larger it may develop skip areas, meaning patches of normal-looking skin within the lesion that create a mottled appearance. Because it stays flat and smooth for a long time, people often dismiss it as a sun spot. Any brown mark on the face that gradually changes shape or develops new shades of color over months or years is worth having checked.
Melanoma Under Nails and on Palms and Soles
Acral lentiginous melanoma develops in places most people don’t think to check: the soles of the feet, palms of the hands, and under fingernails or toenails. It appears as a dark brown or black discoloration that can resemble a bruise or stain, but unlike a bruise it doesn’t fade. Instead, it grows.
When melanoma develops under a nail, it’s called subungual melanoma. In about 65% of cases, it first appears as a dark vertical streak running the length of the nail. Streaks wider than 3 mm, streaks that are wider near the cuticle than at the tip, and streaks with irregular borders are all concerning features. One especially telling sign is the Hutchinson sign, where dark pigment extends beyond the nail onto the surrounding skin at the cuticle or sides of the nail. As it progresses, the nail may crack, break, or lift away from the nail bed.
This type of melanoma occurs equally across all races and skin tones, but it accounts for the majority of melanomas diagnosed in people of color. Because overall melanoma rates are lower in people with darker skin, both patients and doctors may be less alert to it. Checking your palms, the spaces between your toes, and the soles of your feet during self-exams is important regardless of your skin tone.
How Melanoma Differs From Common Lookalikes
Several harmless skin growths can mimic melanoma’s appearance. Seborrheic keratoses are among the most common. These waxy, slightly raised, “stuck-on” looking spots are benign and extremely common after age 40. They can be dark brown or even black, which sometimes triggers alarm. The key visual difference is texture: seborrheic keratoses tend to have a rough, waxy, or scaly surface with a uniform internal pattern, while melanomas typically show more variation in color and structure across the lesion. A seborrheic keratosis looks like it was pasted onto the skin; a melanoma looks like it’s part of the skin.
Atypical moles (also called dysplastic nevi) can also look suspicious, with irregular borders and mixed colors. These moles are benign but indicate a higher overall risk for melanoma, so they’re worth monitoring over time. The critical difference is change. An atypical mole that has looked the same for years is far less concerning than one that is actively shifting in size, shape, or color.