Skin cancer doesn’t have one single look. It can show up as a pearly bump, a scaly patch, a dark streak under a fingernail, or a mole that slowly changes shape. The three main types, basal cell carcinoma, squamous cell carcinoma, and melanoma, each have distinct visual patterns, and knowing what to scan for makes a real difference in catching them early.
Basal Cell Carcinoma
Basal cell carcinoma is the most common skin cancer, and it often looks deceptively minor. On lighter skin, it typically appears as a shiny, translucent bump with a pearly white or pink tone. You can sometimes see tiny blood vessels running through or around it. On brown and Black skin, the same bump tends to look brown or glossy black, and those small blood vessels are harder to spot.
Not all basal cell carcinomas look like bumps, though. Some present as a flat, scaly patch with or without a raised edge. Others appear as a brown, black, or blue lesion with dark spots and a slightly raised, translucent border. One particularly sneaky form looks like a white, waxy, scar-like area with no clearly defined border. It can be mistaken for an old injury. Any of these may bleed, scab over, and then seem to heal before opening up again.
Squamous Cell Carcinoma
Squamous cell carcinoma tends to look rougher and more irritated than basal cell. It often shows up as a firm bump (called a nodule) that can be skin-colored, pink, red, brown, or black depending on your skin tone. Another common form is a flat sore topped with a scaly crust that doesn’t resolve.
Watch for a new sore or raised area forming on an old scar. On the lips, squamous cell carcinoma can appear as a rough, scaly patch that may crack open into a sore. It can also develop inside the mouth as a persistent sore or rough patch. The key signal is a wound or scab that won’t heal within about two months, or a scaly spot that keeps coming back in the same place.
Melanoma and the ABCDE Rule
Melanoma is less common than basal or squamous cell carcinoma but far more dangerous. It usually develops in or near an existing mole, though it can also appear on previously clear skin. The National Cancer Institute uses the ABCDE rule to describe the warning signs of early melanoma:
- Asymmetry: One half of the mole doesn’t match the other.
- Border: The edges are ragged, notched, or blurred, and pigment may spread into the surrounding skin.
- Color: The mole contains multiple shades of brown, black, or tan, sometimes mixed with areas of white, gray, red, pink, or blue.
- Diameter: Most melanomas are larger than 6 millimeters across (roughly the size of a pencil eraser), though they can start smaller.
- Evolving: The mole has visibly changed in size, shape, or color over recent weeks or months.
A mole doesn’t need to check every box to be suspicious. Any single one of these features, especially a mole that’s actively changing, is worth getting looked at.
The “Ugly Duckling” Sign
Beyond the ABCDE criteria, there’s a simpler pattern-recognition approach. Most of your moles tend to look similar to each other. The “ugly duckling” sign means scanning your skin for the one mole that looks noticeably different from the rest, the outlier in size, color, or shape. In a randomized study comparing laypeople trained in either the ABCDE rule or the ugly duckling approach, both groups caught melanoma at nearly the same rate (99% and 100% sensitivity). But the ugly duckling group was significantly more accurate overall, making fewer false alarms. In practice, using both methods together gives you the best chance of spotting something early.
What Skin Cancer Looks Like on Darker Skin
Skin cancer images in medical textbooks overwhelmingly show lighter skin, which can make it harder for people with darker skin tones to recognize what to look for. Basal cell carcinoma on darker skin may appear lighter or darker than a person’s usual skin tone rather than the classic pearly pink. Squamous cell nodules can look brown or black rather than red.
Melanoma is less common in people with darker skin, but when it does occur, it’s more likely to appear in places that don’t get much sun: the palms of the hands, the soles of the feet, or under the nails. These are called acral melanomas, and they’re more common in older adults and people with darker skin tones. Because these locations are easy to overlook, acral melanomas are often caught later, which makes intentional self-checks of your hands, feet, and nail beds especially important.
Melanoma Under the Nails
Subungual melanoma, which grows under a fingernail or toenail, has a distinctive appearance. It typically looks like a dark brown or black line running vertically from the base of the nail to the tip, as though someone drew a streak with a marker. The line usually starts narrower than 3 millimeters but can widen over time.
One important sign is called the Hutchinson sign, where the dark pigment spreads beyond the nail itself and discolors the surrounding skin at the cuticle or fingertip. If you notice a new dark band on a single nail, especially one that’s getting wider or bleeding, that warrants a closer look from a dermatologist.
Precancerous Spots
Not every worrisome spot is cancer yet. Actinic keratoses are precancerous patches caused by cumulative sun damage, and they’re worth knowing about because they can progress to squamous cell carcinoma if left alone. You can often feel one before you see it: a small rough patch, like sandpaper, on sun-exposed skin.
Visually, they show up as scaly, raised bumps that may look like pimples or irritated skin. They can be red, pink, skin-colored, or gray. When several appear at once, they can resemble a rash or acne breakout. On the lips, an actinic keratosis looks like a persistently dry, scaly patch that never fully heals or keeps returning. Flat versions can easily be mistaken for age spots.
Growths That Look Like Cancer but Aren’t
Seborrheic keratoses are one of the most common benign growths that get mistaken for skin cancer. They’re sometimes called “barnacles of aging” and appear as slightly raised, waxy, discolored patches. They can range from white to black and show up anywhere on the body. People often describe them as odd-looking scabs that seem stuck on top of the skin.
The key differences: seborrheic keratoses are typically flat, waxy, and painless. They don’t change rapidly, and they tend to have a uniform, “pasted on” quality. Melanoma, by contrast, is more likely to be asymmetrical, contain multiple colors, measure larger than 6 millimeters, and change over time. If a growth you assumed was a harmless barnacle starts shifting in shape or color, that’s a reason to have it evaluated. The distinction isn’t always obvious to the naked eye, and dermatologists occasionally biopsy seborrheic keratoses just to be certain.
Rare Types
Merkel cell carcinoma is uncommon but aggressive. It typically appears as a painless pink, red, or purple lump on the skin, often on sun-exposed areas like the face, head, or neck. Because it looks so unremarkable, similar to a cyst or bug bite, it’s easily dismissed. Merkel cell tends to grow quickly, which is actually a useful clue: a firm, painless lump that appeared recently and is growing fast deserves prompt attention.