Skin cancer shows up as a visible change on your skin, and learning what to look for can help you catch it early, when treatment is most effective. Melanoma detected at a localized stage has a 97.6% five-year survival rate, compared to just 16.2% when it has spread to distant parts of the body. The good news: about 83% of melanomas are caught early. Knowing the warning signs puts you in a strong position to be one of them.
The ABCDE Rule for Melanoma
Melanoma is the most dangerous form of skin cancer, but it also follows a recognizable pattern. Dermatologists use five features, known as the ABCDEs, to flag suspicious moles and spots:
- Asymmetry. One half of the mole doesn’t match the other. Normal moles tend to be roughly symmetrical.
- Border. The edges are ragged, notched, or blurred rather than smooth. The pigment may seem to bleed into the surrounding skin.
- Color. Instead of one uniform shade, you see a mix of brown, tan, and black, sometimes with patches of white, gray, red, pink, or blue.
- Diameter. Most melanomas are larger than 6 millimeters across (about the size of a pencil eraser), though they can be smaller.
- Evolving. The spot has changed in size, shape, or color over the past few weeks or months. Any mole that looks different than it did recently deserves attention.
Not every melanoma checks all five boxes, especially early on. Even one of these features on a new or changing spot is worth having examined.
The “Ugly Duckling” Sign
Your moles tend to look like each other. They share a general color, size, and shape that’s unique to your skin. A melanoma often stands out as the one spot that doesn’t fit the pattern, the “ugly duckling” among your other moles. In a study published in the Journal of the American Academy of Dermatology, this approach detected melanoma with 86% sensitivity across all skill levels, from expert dermatologists to people with no medical training. All five melanomas in the study were identified as ugly ducklings. If one spot simply looks “off” compared to the rest of your moles, that instinct is worth acting on.
What Non-Melanoma Skin Cancers Look Like
Basal Cell Carcinoma
Basal cell carcinoma is the most common skin cancer. On lighter skin, it often appears as a shiny, slightly translucent bump that looks pearly white or pink. Tiny blood vessels may be visible on or near the surface. On darker skin, the same type of growth may appear brown or glossy black with a rolled border.
Not all basal cell carcinomas look like bumps. Some show up as a flat, scaly patch that slowly grows larger over time. Others resemble a white, waxy, scar-like area with no clear edge. A hallmark of basal cell carcinoma is a sore that bleeds, scabs over, and then returns without fully healing.
Squamous Cell Carcinoma
Squamous cell carcinoma often starts as a rough, scaly patch or a firm, red bump. It can look crusty, bleed easily, or develop a depression in the center. These lesions tend to appear on sun-exposed areas like the face, ears, neck, forearms, and backs of the hands. Unlike a normal scrape or dry patch, they persist for weeks and don’t respond to moisturizer or basic wound care.
Pre-Cancerous Spots to Watch
Actinic keratoses are rough, dry, scaly patches that develop on sun-exposed skin. They’re typically smaller than an inch across, often pink, red, or brown, and feel like sandpaper when you run your finger over them. Some develop a hard, wart-like surface. You’ll find them most commonly on the face, lips, ears, scalp, neck, forearms, and backs of the hands.
These patches aren’t cancer yet, but they can become squamous cell carcinoma if left alone. The estimated progression rate is 5% to 10%. If you notice persistent rough patches in sun-exposed areas that don’t resolve on their own, they’re worth having checked and treated before they progress.
Symptoms You Can Feel, Not Just See
Skin cancer isn’t always just a visual change. Some spots itch persistently in one localized area. Others bleed spontaneously or with minimal contact, then crust over and bleed again. A mole that becomes tender or sore without an obvious cause is also worth noting. Any spot that bleeds, itches, or crusts repeatedly should be evaluated, even if it doesn’t look dramatically different from surrounding skin.
Skin Cancer on Darker Skin
People with very dark skin have more natural protection against UV radiation, but skin cancer still occurs. The type that disproportionately affects Black, Hispanic, and Asian individuals is acral lentiginous melanoma, which appears on the palms of the hands, soles of the feet, and under the nails. It accounts for only 2 to 3% of all melanoma cases, but it’s the most common melanoma subtype in people of color.
The challenge is that these locations aren’t where most people think to look for skin cancer, and the presentation can be subtle: a dark streak under a fingernail or toenail, a discolored patch on the sole of the foot, or an irregularly shaped dark spot on the palm. Because it’s frequently under-recognized, people with darker skin tones tend to be diagnosed at more advanced stages, with thicker tumors and worse outcomes. Checking your palms, soles, nail beds, and the spaces between your toes is especially important.
How to Do a Self-Exam
The best time to check your skin is after a bath or shower, in a well-lit room with a full-length mirror. You’ll also want a hand mirror and a comb for your scalp. The goal is to look at every inch of skin on your body, systematically, so you don’t skip areas.
Start by facing the mirror and examining your entire front, then turn and check your back. Raise your arms and check your underarms and both sides of each arm, including the backs of your upper arms, which are easy to miss. Bend your elbows and look at your forearms on all sides. Check the tops and palms of your hands. Examine both legs, front and back. Look at your buttocks, genital area, and between your buttocks. Use the hand mirror and comb to work through your scalp section by section. Check your face, neck, and the back of your neck. Finally, sit down and examine your feet: the tops, the soles, the spaces between your toes, and your toenails. For areas you can’t see well, ask someone you trust to help.
Doing this regularly means you’ll notice when something changes. That change, more than any single feature, is what matters most.
What Happens During a Professional Skin Check
If you or your doctor spots something suspicious, the next step is a biopsy, where a small sample of skin is removed and examined under a microscope. There are three common types, and which one your dermatologist uses depends on the spot’s size, depth, and location.
A shave biopsy scrapes a thin layer from the skin’s surface. It’s quick, doesn’t require stitches, and works well for shallow, surface-level growths. A punch biopsy uses a small circular tool to remove a deeper core of skin, including layers below the surface. This one usually needs a stitch or two. An excisional biopsy removes the entire suspicious area along with a margin of healthy skin around it. It requires stitches and is used when a doctor wants to remove the whole lesion at once.
All three are done with local numbing and are outpatient procedures. Results typically come back within one to two weeks.
Who’s at Higher Risk
Your skin type plays a significant role in your risk level. People with very fair skin that always burns and never tans (Fitzpatrick types 1 and 2) are at the highest risk for skin cancer. Those with medium skin that sometimes burns (types 3 and 4) face moderate risk, though tanning itself is a sign of UV damage. People with deeply pigmented skin that rarely or never burns (types 5 and 6) have more built-in UV protection, but still develop skin cancer, particularly in areas that don’t get sun exposure.
Beyond skin type, other factors increase your risk: a history of blistering sunburns, regular use of tanning beds, a large number of moles (50 or more), a family history of melanoma, a weakened immune system, and a personal history of any prior skin cancer. Having one or more of these factors doesn’t mean you’ll develop skin cancer, but it does mean regular self-exams and professional skin checks are more important for you.