Melanoma often looks like an unusual mole: a flat or slightly raised spot with uneven color, irregular edges, and a diameter larger than 6 millimeters (about the size of a pencil eraser). But melanoma doesn’t always follow that pattern. Some are tiny, some are pink instead of brown, and some grow in places you’d never think to check, like under a toenail. Knowing the full range of what melanoma can look like gives you a real advantage in catching it early.
The ABCDE Features of Early Melanoma
The most widely used framework for spotting melanoma is the ABCDE rule, developed to describe the features of early-stage disease. Each letter flags a visual clue:
- 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: Multiple shades appear within the same spot. You might see brown, tan, and black alongside areas of white, gray, red, pink, or blue.
- Diameter: Most melanomas are larger than 6 millimeters across, but they can be smaller. In one study of 292 melanoma patients, 28% had tumors that measured 6 millimeters or less, and more than a third of those smaller tumors were already invasive.
- 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 catch most melanomas, but not all. The diameter rule in particular has significant limitations. A small spot that meets the other criteria should not be dismissed just because it’s under 6 millimeters.
How the Four Main Types Look Different
Superficial Spreading Melanoma
This is the most common type. It starts as a flat or slightly raised brown spot with areas of black, blue, or pink. The borders are irregular and asymmetric, and the spot is usually wider than 6 millimeters. What makes this type distinctive is that it grows outward across the skin surface for months or even years before it starts growing deeper. That slow horizontal spread is actually an advantage for early detection because the spot is visible for a long time before it becomes dangerous.
Nodular Melanoma
Nodular melanoma is the most aggressive form in terms of speed. Instead of spreading outward first, it grows downward into the skin almost immediately. It typically appears as a dome-shaped bump or raised nodule, dark brown to black in color. It can look similar to a blood blister or a small blood vessel growth. This type develops rapidly over weeks to months, which means a new bump that appeared recently and is growing fast warrants prompt evaluation. About 5% of nodular melanomas have no dark pigment at all, making them even harder to recognize.
Lentigo Maligna Melanoma
This type tends to show up on chronically sun-damaged skin, especially the face, in older adults. It starts as a large, flat patch of uneven brown pigmentation, often exceeding 3 centimeters. Many years can pass before the spot develops darker brown-to-black areas or a raised blue-black nodule, which signals it has become invasive. Because it looks like a sun spot for so long, it’s easy to overlook.
Acral Lentiginous Melanoma
This type appears on the palms, soles of the feet, and under fingernails or toenails. It usually looks like an unevenly pigmented black or brown spot on the palm or sole that stands out from the rest of your skin and grows over time. When it involves a nail, it shows up as a pigmented streak or band of color running from the cuticle to the tip of the nail. Acral lentiginous melanoma is extremely aggressive and progresses quickly from surface growth to deep invasion. A screening acronym called CUBED can help: Color that’s unusual, Uncertain diagnosis, Bleeding, Enlargement, and Delay in healing.
Melanoma That Doesn’t Look Like Melanoma
Not all melanomas are dark. Amelanotic melanomas lack the pigment that makes most melanomas brown or black. They often appear red, pink, or even skin-colored, which makes them particularly dangerous because they don’t trigger the usual alarm bells. In studies, red amelanotic melanomas averaged about 7.7 millimeters in diameter, smaller than typical pigmented melanomas, and all were already growing deeper into the skin at the time of diagnosis.
Because they don’t look like what people expect melanoma to look like, these lesions are frequently misdiagnosed. About 35% of misdiagnosed red amelanotic melanomas were initially thought to be basal cell carcinoma. Others were mistaken for eczema, warts, bug bites, scar tissue, or benign skin growths. If you have a pink or red spot that doesn’t heal, bleeds easily, or keeps changing, it’s worth having it examined even though it doesn’t fit the classic melanoma description.
The “Ugly Duckling” Approach
Beyond examining individual spots, one of the most effective ways to spot melanoma is to compare a mole to all your other moles. Most people have a “signature pattern” to their moles: they tend to look similar to each other in size, shape, and color. A melanoma often stands out as the one that looks nothing like the rest. Dermatologists call this the ugly duckling sign.
In a study of 80 patients, dermatologists identified all melanomas as ugly ducklings, and using this comparison method alongside individual spot analysis reduced the number of moles flagged for biopsy by nearly sevenfold. In practical terms, this means you don’t need to memorize a checklist for every mole on your body. Instead, look for the outlier: the one spot that’s darker, larger, a different shape, or a different color than everything else on your skin.
What Melanoma Looks Like in Children
Melanoma is rare in children, but when it does occur, it often breaks all the usual rules. A study found that 60% of children under 10 and 40% of adolescents with melanoma did not meet the traditional ABCDE criteria. Their melanomas were symmetric, had regular borders, were a single uniform color, and measured 6 millimeters or smaller. Because of this mismatch, up to 82% of pediatric melanoma diagnoses were delayed more than six months after the spot was first noticed.
Researchers have proposed modified criteria for children: A for amelanotic (no dark pigment), B for bleeding or bump, C for color uniformity, D for de novo (brand new, any diameter), and E for evolution. In other words, a new bump on a child that bleeds or keeps changing should be taken seriously even if it looks nothing like a “typical” mole.
Spots That Look Like Melanoma but Aren’t
Seborrheic keratoses are among the most common melanoma mimics. These are waxy, stuck-on-looking growths that can be brown or black and develop with age. The key visual difference is texture. Seborrheic keratoses tend to have a uniform, waxy surface that looks almost pasted onto the skin, while melanomas have more variation in surface texture, brightness, and the relationship between neighboring areas of color. Seborrheic keratoses also don’t evolve the way melanomas do. They may darken slightly or grow slowly over years, but they don’t change shape or develop new colors over weeks.
Other common look-alikes include normal moles (which are symmetric, evenly colored, and stable over time), age spots (uniformly tan or light brown, flat, with smooth edges), and cherry angiomas (small, bright red, dome-shaped spots caused by blood vessel clusters). The distinguishing factor with melanoma is almost always change: a spot that’s evolving in size, shape, color, or texture when nothing else on your skin is doing the same.
Where to Look
Melanoma can develop anywhere on the body, including areas that rarely see sunlight. The most commonly missed locations are the soles of the feet, between the toes, under fingernails and toenails, the scalp, behind the ears, and the back (where you can’t easily see). Acral lentiginous melanoma specifically targets the palms, soles, and nail beds, and it’s the most common type of melanoma in people with darker skin tones.
Under a nail, melanoma typically shows up as a dark vertical streak that starts at the cuticle and extends toward the tip. If pigment also spreads onto the skin around the nail (the cuticle or nail fold), that’s a particularly concerning sign. A full skin check means looking at every surface, including the ones you’d normally skip.