Skin cancer doesn’t have one single look. It can appear as a pearly bump, a scaly patch, a dark streak under a nail, or even a pink spot that barely stands out from the surrounding skin. The type of skin cancer, your skin tone, and where it develops on your body all change what you’ll see. Here’s what to look for across every major type.
Melanoma and the ABCDE Rule
Melanoma is the most dangerous form of skin cancer, and it’s the one most people picture: an unusual-looking mole. The standard screening tool is the ABCDE rule, developed by the National Cancer Institute:
- Asymmetry: One half of the mole doesn’t match the other.
- Border: The edges are ragged, notched, or blurred, and pigment may spread into surrounding skin.
- Color: The mole contains multiple shades of brown, black, red, white, or blue rather than one uniform color.
- Diameter: Most melanomas are larger than 6 millimeters wide (about the size of a pencil eraser), though they can be smaller.
- Evolving: The mole is changing in size, shape, or color over weeks or months.
These criteria catch many melanomas, but not all. Nodular melanoma, which grows downward into the skin rather than spreading outward, often skips the classic warning signs. It typically shows up as a firm, dome-shaped growth that may look like a blood blister. It develops fast, usually over several weeks, and doesn’t always follow the flat, irregular-bordered pattern people expect. For nodular melanoma, doctors use a simpler checklist: is it elevated, firm, and growing?
Melanoma That Doesn’t Look Dark
About 5 percent of melanomas are amelanotic, meaning they lack the dark pigment most people associate with the disease. Instead, they appear as a pink or red spot on the skin. Because they blend in so easily and resemble harmless irritations, amelanotic melanomas are frequently diagnosed at a later stage compared with brown, black, or blue melanomas. If you have a pink bump or patch that won’t heal and doesn’t have an obvious cause, it’s worth having it checked.
Basal Cell Carcinoma
Basal cell carcinoma (BCC) is the most common skin cancer worldwide, and it often looks surprisingly subtle. The classic form is a slightly transparent, dome-shaped bump with a pearly or waxy surface. Tiny blood vessels may be visible running through or around it. Over time, it can bleed, scab over, and then bleed again in a cycle that doesn’t fully resolve.
On lighter skin, BCC typically appears skin-colored or pink. On brown and Black skin, it often looks brown or glossy black with a rolled, raised border. Not every BCC is a bump, though. Some appear as flat, scaly patches that slowly enlarge over months or years. Others look like white, scar-like lesions with no clearly defined edge, making them easy to dismiss as a minor skin change.
Squamous Cell Carcinoma
Squamous cell carcinoma (SCC) tends to look rougher and more irritated than BCC. Common presentations include a firm nodule on the skin, a flat sore topped with a scaly crust, or a raised wart-like growth. Colors range from pink and red to brown and black, depending on skin tone.
SCC has a few patterns that catch people off guard. It can develop on the lip as a rough, scaly patch that eventually opens into a sore. It can appear inside the mouth as a persistent rough patch or sore. And it sometimes grows on top of an old scar or a wound that healed long ago, showing up as a new raised area where the skin had been flat.
Pre-Cancerous Spots
Actinic keratoses are rough, dry, scaly patches that develop on sun-exposed skin, usually less than an inch across. They feel like sandpaper when you run your finger over them. Colors range from pink to red to brown, and some develop a hard, wart-like surface. These aren’t cancer yet, but a small percentage progress to squamous cell carcinoma if left untreated. They’re common on the face, scalp (especially in people with thinning hair), forearms, and the backs of the hands.
Skin Cancer on Darker Skin
People with darker skin tones develop skin cancer less frequently overall, but when they do, it often appears in places that don’t get much sun. The most common melanoma in people with dark skin is acral lentiginous melanoma, which develops on the palms, soles of the feet, fingers, toes, and under the nails.
Under a nail, it typically looks like a dark band running lengthwise. On a palm or sole, it appears as a dark patch that may be mistaken for a bruise or stain. Pay particular attention if a dark band under your nail starts to widen or if pigment spreads into the skin around the nail. These changes are easy to overlook during routine skin checks because most people focus on moles on their arms, back, and face.
Merkel Cell Carcinoma
Merkel cell carcinoma is rare but aggressive. It shows up as a firm, painless bump on the skin that grows noticeably fast, often over just a few weeks. The bump can look pink, purple, red-brown, or match the surrounding skin color. One visual clue is asymmetry: the two halves of the bump don’t mirror each other. Because it’s painless and can resemble a cyst or insect bite, people often wait too long before having it evaluated. This cancer spreads quickly, so rapid growth of any new skin bump deserves prompt attention.
Skin Cancer in Hidden Areas
Skin cancer can develop in places you’d never think to look. Mucosal melanoma grows on the moist tissue lining the inside of the body, including the mouth, nasal passages, rectum, and genital area. In the mouth, it may appear as a lump on the tongue that keeps growing or a sore that won’t heal. Rectal mucosal melanoma can cause a mass, bleeding, pain, or persistent itching. In the vaginal or vulvar area, signs include unusual bleeding (especially between periods or after menopause), a visible lump, or itching that doesn’t respond to typical treatments.
These cancers are rare, but they’re worth knowing about because they develop in areas that standard skin exams don’t cover. Symptoms are often attributed to hemorrhoids, canker sores, or infections before the correct diagnosis is made.
The One Pattern That Ties Them Together
Across every type of skin cancer, the single most reliable warning sign is change. A new spot that wasn’t there a few months ago. A bump that keeps growing. A sore that heals and then reopens. A mole that shifts in color or shape. Skin cancers don’t stabilize on their own; they keep evolving. Paying attention to what’s different on your skin, rather than memorizing a single image of what cancer “should” look like, is the most practical way to catch it early.