Early skin cancer usually shows up as a small change you can see or feel on your skin: a shiny bump, a scaly patch that won’t go away, a sore that keeps reopening, or a mole that looks different from all your others. The tricky part is that skin cancer doesn’t have one single appearance. It varies by type, by skin tone, and by location on the body. Here’s what to actually look for.
Basal Cell Carcinoma: The Most Common Type
Basal cell carcinoma accounts for the majority of skin cancers, and it often looks deceptively minor. On lighter skin, it typically appears as a firm, raised, round growth that’s shiny and pink or red. On darker skin tones, the same growth tends to be brown, black, or blue. Sometimes it matches your skin color entirely, which makes it easy to dismiss.
A few patterns are worth memorizing. One is a bump with a dip or crater in the center, almost like a donut shape. That center may scab over and bleed, then seem to heal, then bleed again. Another is a rough, scaly patch that feels like sandpaper. A spot that looks like a freckle or age spot but feels scaly when you run your finger over it can also be basal cell carcinoma. The hallmark clue for this cancer is a sore that heals and returns, or simply never heals at all.
Squamous Cell Carcinoma: Scaly, Crusty, Persistent
Squamous cell carcinoma is the second most common skin cancer, and it looks different from basal cell. The classic early sign is a flat sore with a scaly crust on top. On the lips, it often starts as a rough, scaly patch that may eventually break open into a sore. These lesions tend to form in areas with a history of sun damage, but they can also develop in scars, old burns, or chronic wounds.
The key signal is persistence. A sore or scab that hasn’t healed within about two months, or a flat scaly patch that won’t go away no matter what you do, warrants a closer look. Squamous cell carcinoma doesn’t resolve on its own the way a normal scrape or irritation would.
Pre-Cancerous Spots That Can Progress
Before squamous cell carcinoma fully develops, it often starts as an actinic keratosis, a rough, sandpaper-textured patch caused by years of sun exposure. These are small (usually under a centimeter), pink or skin-colored, and easier to feel than to see. You might notice them on your face, ears, scalp, forearms, or the backs of your hands.
Not every actinic keratosis becomes cancer, but they sit on a spectrum. Warning signs that one may be progressing include rapid growth, bleeding, ulceration, hardening underneath the surface, or a diameter larger than 1 centimeter. If a previously flat, subtle patch starts thickening or becoming painful, that shift matters.
Melanoma and the ABCDE Rule
Melanoma is less common than basal or squamous cell carcinoma but far more dangerous. It develops in the pigment-producing cells of the skin and can spread quickly. The ABCDE criteria, developed by the National Cancer Institute, give you a practical 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 and round. Pigment may spread into surrounding skin.
- Color: The mole has uneven color, with mixtures of brown, black, tan, red, or blue within a single spot.
- Diameter: Most melanomas are larger than 6 millimeters (about the width of a pencil eraser), though they can start smaller.
- Evolving: Any change in size, shape, or color over weeks to months is the single most important warning sign.
Some aggressive forms, particularly nodular melanoma, can grow dangerously fast, becoming life-threatening in as little as six weeks. This type often appears as a raised, dome-shaped bump rather than a flat, spreading mole, so it doesn’t always follow the classic ABCDE pattern. Any new bump that’s growing noticeably over a few weeks deserves attention.
Melanoma That Isn’t Dark
About 5 percent of melanomas are amelanotic, meaning they lack the dark pigment most people associate with skin cancer. These appear as pink, red, or skin-colored spots. Because they don’t look like a typical mole, they’re frequently mistaken for a pimple, bug bite, or minor irritation. This confusion means amelanotic melanomas are often diagnosed at a later stage than pigmented ones. If you have a pink or reddish bump that persists for several weeks without explanation, it’s worth having a dermatologist examine it.
Skin Cancer Under the Nails
Subungual melanoma develops beneath a fingernail or toenail and is easy to overlook. It typically appears as a dark brown or black vertical streak running from the base of the nail toward the tip. Early on, the streak is usually less than 3 millimeters wide, but it can widen over time, especially at the base of the nail. The color may be uneven, with varying shades of brown and black, and the line may become irregular in shape or multiply into additional streaks.
This type is more common on the thumb and big toe and occurs across all skin tones. It’s sometimes mistaken for a bruise under the nail, but a bruise grows out with the nail over weeks, while a melanoma streak stays in place or gets wider.
The Ugly Duckling Approach
Beyond examining individual spots, one of the most effective self-screening strategies is looking for the outlier. Most of your moles tend to resemble each other in size, shape, and color. The “ugly duckling” is the one mole that doesn’t fit the pattern. A 2017 study in JAMA Dermatology found that dermatologists who used this comparative approach were just as accurate at identifying melanoma as those who analyzed each mole individually, and they flagged fewer harmless moles for unnecessary biopsies. When you check your skin, step back and scan for the mole that stands out from the rest.
What Skin Cancer Doesn’t Look Like
It helps to know what’s probably harmless. Seborrheic keratoses are extremely common benign growths that can look alarming. They appear as waxy, raised patches that look almost “stuck on” to the skin, like a blob of candle wax. They range from light tan to black and can show up anywhere on the body. Unlike melanoma, they tend to have a uniform texture across the surface and don’t change rapidly. They’re painless and flat to slightly raised. If a growth looks waxy, feels stuck on, and hasn’t changed in months, it’s much more likely to be a seborrheic keratosis than cancer.
How to Check Your Skin
The Skin Cancer Foundation recommends a head-to-toe self-exam once a month. You’ll need a full-length mirror, a hand mirror, and good lighting. Start with your hands, checking your palms, the backs of your hands, between your fingers, and under each fingernail. Move up your forearms and upper arms, including the underarms. Examine your neck, chest, and torso, lifting the breasts to see the undersides. Use the hand mirror with the full-length mirror to inspect your upper back, shoulders, and the back of your neck. Then check your lower back, buttocks, and the backs of both legs.
The point of monthly checks isn’t to diagnose anything yourself. It’s to notice change. When you know what your skin normally looks like, a new spot or a shifting mole becomes obvious in a way it never would if you weren’t paying attention. That awareness is what catches skin cancer early, when it’s most treatable.