Skin cancer doesn’t have one single look. It can appear as a shiny bump, a scaly patch, a dark streak under a fingernail, or a sore that won’t heal. The specific appearance depends on the type of skin cancer, and each type has distinct visual clues worth knowing. Most skin cancers fall into three main categories: basal cell carcinoma, squamous cell carcinoma, and melanoma.
Basal Cell Carcinoma
Basal cell carcinoma is the most common type of skin cancer, and it tends to grow slowly. On lighter skin, it often shows up as a firm, raised, round growth that looks shiny and pink or red. On darker skin tones, the same kind of bump tends to appear brown, black, or blue. Sometimes the growth is the same color as the surrounding skin, making it harder to spot visually.
One telltale feature is a round area with a dip or depression in the center. That central dip may scab over and bleed repeatedly. Basal cell carcinoma can also look like a rough, scaly patch, and some people develop several patches at once. A spot that resembles a freckle or age spot but feels scaly to the touch is another presentation. Perhaps the most important warning sign: a sore that heals and then returns, or one that simply never heals completely.
Squamous Cell Carcinoma
Squamous cell carcinoma is the second most common type and tends to be more noticeable than basal cell. It typically appears as a thick, rough, scaly patch that may crust or bleed. Some look like warts. Others look like open sores that never fully close.
A persistent red patch with irregular borders that occasionally crusts or bleeds is a classic presentation. So is an open sore that bleeds, scabs over, and then persists for weeks without resolving. These growths tend to develop on sun-exposed areas like the face, ears, neck, hands, and forearms, though they can appear anywhere on the body.
Melanoma and the ABCDE Rule
Melanoma is less common than the other two types but far more dangerous because it can spread quickly. The ABCDE rule is the most widely used framework for spotting it early:
- Asymmetry: One half of the mole doesn’t match the other half.
- Border: The edges are ragged, notched, or blurred rather than smooth. Pigment may spread into the surrounding skin.
- Color: The color is uneven. You might see shades of black, brown, and tan mixed together, sometimes with areas of white, gray, red, pink, or blue.
- Diameter: Most melanomas are larger than 6 millimeters wide (about the size of a pencil eraser), though they can start smaller.
- Evolving: The mole has changed in size, shape, or color over the past few weeks or months.
Not every melanoma checks all five boxes. A mole that meets even one or two of these criteria is worth having examined.
The Ugly Duckling Sign
Beyond the ABCDE rule, there’s a simpler concept that catches melanomas the rule might miss. Most people’s 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’s the “ugly duckling” sign. It doesn’t matter whether the mole is large or small. What matters is that it doesn’t match the pattern of your other moles.
Melanoma Under the Nail
Melanoma can also develop beneath a fingernail or toenail, where it looks nothing like a typical mole. It usually appears as a dark vertical streak running from the bottom of the nail to the top. The streak may start narrow and gradually widen to cover the entire nail. In more advanced cases, the dark pigment spreads beyond the nail into the surrounding skin and cuticle, a feature known as the Hutchinson sign. This type of melanoma is more common on the thumb and big toe and occurs at higher rates in people with darker skin tones.
Pre-Cancerous Spots
Actinic keratoses aren’t skin cancer yet, but they can develop into squamous cell carcinoma if left untreated. They appear as flat to slightly raised, scaly, crusty patches. Colors range from red, tan, and pink to brown, silvery, or skin-toned. Some develop a small horn-shaped bump.
These spots are often easier to feel than to see. The skin may feel dry and rough, like sandpaper, or raw and sensitive. Some people notice itching, pricking, or a burning sensation. They typically show up on areas that have received years of sun exposure: the face, scalp, ears, forearms, and backs of the hands.
Rare But Fast-Growing Types
Merkel cell carcinoma is uncommon but aggressive. It appears as a bump that grows quickly, sometimes doubling in size within weeks. The bump may look pink, purple, red-brown, or the same color as the surrounding skin. Because it’s painless and can resemble a cyst or insect bite, it’s easy to dismiss. The rapid growth rate is the key distinguishing feature.
How Long to Watch a Spot
Any new or changing spot on your skin that persists for two or more weeks warrants a closer look from a dermatologist. That includes sores that don’t heal, bumps that keep growing, patches that bleed and crust repeatedly, or moles that are changing shape or color. Two weeks is the general threshold recommended by MD Anderson Cancer Center for deciding when a spot has stuck around long enough to need professional evaluation.
What Skin Cancer Does Not Look Like
Skin cancer rarely hurts in its early stages. Most people notice it because of how it looks, not how it feels. It also doesn’t always appear on sun-exposed skin. Melanoma can develop between toes, on the soles of the feet, on the palms, under nails, and even on skin that rarely sees sunlight. On darker skin tones, skin cancer is more likely to appear in these less obvious locations, which contributes to later-stage diagnoses.
Skin cancer also doesn’t always look dramatic. Some basal cell carcinomas resemble a minor blemish or a small shiny patch. Some squamous cell carcinomas look like persistent dry skin. The most dangerous spots aren’t necessarily the most alarming-looking ones. What matters most is change: a spot that’s new, growing, bleeding, or different from everything else on your skin.