Melanoma typically appears as an unusual mole or spot on the skin that stands out because of its irregular shape, uneven color, or changing appearance. It can look dramatically different depending on the type, ranging from a flat, multicolored patch to a raised dark bump to, in some cases, a pink or red spot with no dark pigment at all. Knowing the specific visual features helps you catch it early, when treatment is most effective.
The ABCDE Rule for Spotting Melanoma
Dermatologists use a five-feature checklist to describe the warning signs of early melanoma. Not every melanoma will have all five features, but any one of them is worth getting checked.
- Asymmetry: One half of the mole doesn’t match the other half. A normal mole is roughly symmetrical; melanoma tends to have an uneven, lopsided shape.
- Border: The edges are ragged, notched, or blurred rather than smooth and well-defined. The pigment may look like it’s spreading or bleeding into the surrounding skin.
- Color: Instead of a single uniform shade of brown, you see a mix of colors. Shades of black, brown, and tan are common, but you may also notice areas of white, gray, red, pink, or blue within the same spot.
- Diameter: Most melanomas are larger than 6 millimeters across, roughly the size of a pencil eraser. That said, melanomas can be smaller than this, so any mole that appears to be growing deserves attention regardless of its current size.
- Evolving: The spot has changed in size, shape, or color over the past few weeks or months. Any new symptom, like itching, bleeding, or crusting, also counts as evolution.
The Four Main Types Look Different
Superficial Spreading Melanoma
This is the most common type. It appears as a flat or slightly raised brown patch with irregular, asymmetric borders, often with areas of black, blue, or pink mixed in. These spots are typically wider than 6 millimeters. They tend to grow outward across the skin’s surface for months or even years before growing deeper, which is why early detection rates are relatively good for this type. In men, they show up most often on the head, neck, and trunk. In women, the lower legs are a common location.
Nodular Melanoma
Nodular melanoma looks very different from the flat, patchy appearance most people associate with skin cancer. It typically presents as a dome-shaped bump or raised nodule, dark brown to black in color, and can resemble a blood blister or a small blood vessel growth. This type is more dangerous because it skips the slow, sideways-spreading phase. It grows rapidly downward into the skin over just weeks or months, like an iceberg with most of its mass hidden below the surface. Because it doesn’t always match the classic ABCDE features (it can be round and evenly colored), it’s easier to miss.
Lentigo Maligna Melanoma
This type develops on sun-exposed skin, usually in older adults. It starts as a large, flat patch of discolored skin, often greater than 3 centimeters across. Early on it may look like a large freckle or age spot. Over time, it develops darker brown-to-black areas, and if a raised blue-black nodule appears within the patch, that signals the melanoma has begun growing deeper. This type can take many years to become invasive, making it slow-growing but still requiring treatment.
Acral Lentiginous Melanoma
This type appears in places most people don’t think to check: the palms of the hands, soles of the feet, and under fingernails or toenails. It’s particularly important to know about because it’s the most common form of melanoma in people with darker skin tones. On the palms or soles, it looks like an irregularly shaped dark patch. Under the nail, it shows up as a dark vertical streak running from the base of the nail to the tip, almost as if someone drew a line with a brown or black marker. That streak may be irregular in color, widen over time, or multiply into additional lines. In more advanced cases, the nail may crack, split, lift away from the nail bed, or develop a sore that bleeds. One key warning sign is when the dark pigment spreads beyond the nail itself onto the surrounding skin of the finger or toe, a feature called Hutchinson’s sign.
Melanoma Without Dark Color
About 5 percent of melanomas produce little or no pigment. Called amelanotic melanoma, these spots appear pink, red, or skin-colored rather than brown or black. They can look like a pimple that won’t heal, a small scar, or an irritated patch of skin. Because they don’t match the dark, multicolored appearance people expect from melanoma, they’re often overlooked or mistaken for something harmless. As a result, amelanotic melanoma tends to be diagnosed at a later stage than pigmented types. If you have a pink or reddish spot that persists for several weeks, doesn’t heal, or slowly grows, it’s worth having a dermatologist examine it.
The “Ugly Duckling” Approach
Beyond the ABCDE checklist, there’s a simpler principle that works well in practice: look for the mole that doesn’t match the others. Most people’s moles share a general family resemblance in color, size, and shape. A melanoma often stands out as the outlier, the one spot that looks noticeably different from everything else on your skin. This “ugly duckling” sign is especially useful if you have many moles, because rather than evaluating each one against a checklist, you’re scanning for whichever one breaks the pattern.
The approach has limits. Even dermatologists don’t always agree on which mole qualifies as the ugly duckling in a given patient, and people with very few moles have no baseline pattern to compare against. It works best as a complement to the ABCDE criteria, not a replacement.
What Melanoma Doesn’t Look Like
Some benign growths can mimic melanoma’s appearance closely enough to cause alarm. Seborrheic keratoses, the waxy, “stuck-on” looking brown spots common in middle age and beyond, are one of the most frequent sources of concern. Under magnification, these growths tend to have tiny white cyst-like dots or pore-like openings embedded in their surface, features that melanomas lack. A dermatologist using a dermatoscope can usually distinguish between the two quickly. If a dark spot has a rough, waxy texture and looks like it could be peeled off the skin, it’s more likely a seborrheic keratosis, but any spot you’re uncertain about is worth having examined.
Where to Look on Your Body
Melanoma can develop anywhere on the skin, including places that rarely see sunlight. Monthly self-checks should include areas most people skip: the scalp (use a blow dryer to part your hair), between the toes, the soles of your feet, under your nails, and behind the ears. For the back and other hard-to-see areas, use a full-length mirror combined with a hand mirror, or ask a partner to help.
Pay particular attention to any spot that is new, looks different from your other moles, or has changed recently. Growth over weeks to months is especially concerning, even if the spot is still smaller than 6 millimeters. With nodular melanoma in particular, waiting for a spot to hit that pencil-eraser threshold can mean losing critical time.