What skin cancer looks like on your skin
Skin cancer usually shows up as a new spot on your skin or a change to a spot you already have. The most common sign is a mark that looks different from your other moles or freckles — either darker, larger, oddly shaped, or a color you haven't seen before on your skin. Some skin cancers are flat and scaly. Others are raised and bumpy. A few bleed or ooze without a clear reason.
The spot might itch or feel tender, though many skin cancers don't cause any sensation at all. Size matters: doctors pay attention to spots larger than a pencil eraser, though smaller ones can still be cancer. The key is that it's new or changing — something that wasn't there before or that looks different than it did a few months ago.
Key Takeaways
- Skin cancer often appears as a new spot or a change to an existing mole, and the most common warning sign is a mark that looks different from your other skin spots.
- The ABCDE rule helps you notice suspicious spots: asymmetry (uneven shape), border irregularity, color variation, diameter larger than a pencil eraser, and evolving (changing over time).
- A dermatologist can examine a suspicious spot in person and take a small sample (biopsy) to determine whether it is cancer.
- Finding skin cancer early, before it spreads, makes treatment simpler and outcomes better.
- Checking your own skin once a month and seeing a dermatologist yearly is a straightforward way to catch changes early.
The ABCDE rule for spotting suspicious marks
Doctors use a simple checklist called the ABCDE rule to help people recognize skin cancer. It's not a diagnosis — it's just a way to notice which spots deserve a closer look from a professional.
Asymmetry means the spot is lopsided: if you drew a line through the middle, the two halves wouldn't match. Border refers to the edge — cancerous spots often have jagged, scalloped, or blurry edges instead of a clean line. Color variation means the spot has more than one shade: brown and black mixed together, or tan and red. DiameterEvolving
If a spot has one or more of these features, that's a reason to see a dermatologist. Many benign (non-cancerous) spots will have one or two of these traits, so the rule isn't perfect — but it catches most skin cancers early.
How doctors examine your skin
A dermatologist will look at the suspicious spot with their eyes and often with a magnifying tool called a dermoscope. They'll ask when you first noticed it, whether it's changed, and whether it itches or bleeds. They'll also look at your whole body, because people who have had one skin cancer are more likely to develop another.
If the spot looks concerning, the doctor will usually remove a small sample of skin — a procedure called a biopsy. This takes just a few minutes and uses local numbing medicine so you won't feel pain. The sample goes to a lab where a pathologist (a doctor who studies tissue under a microscope) looks for cancer cells. You'll get results in about a week.
If the biopsy shows cancer, the dermatologist will talk with you about what type it is and what treatment options exist. If it's not cancer, you'll get that news too, and the doctor may recommend how often to check that spot or your skin in general.
Types of skin cancer and how they appear
Melanoma is the most dangerous type. It often appears as an asymmetrical, multicolored spot with an irregular border — the kind the ABCDE rule is designed to catch. Melanoma can be brown, black, red, or even skin-colored.
Basal cell carcinoma is the most common type and usually the slowest-growing. It often looks like a shiny bump, a scar-like patch, or a spot that bleeds and doesn't heal. It's usually found on the face, ears, or neck.
Squamous cell carcinoma is the second most common. It typically appears as a scaly, crusty, or raised bump, often on sun-exposed areas like the face, ears, or hands. It may bleed or feel tender.
All three types are more treatable when caught early, so any spot that concerns you is worth showing to a dermatologist.
Checking your own skin at home
Once a month, spend a few minutes looking at your skin in a mirror under good light. Use a hand mirror to check the back of your neck, your scalp, and between your shoulder blades — places you can't see easily. Have a partner check your back if possible.
Look for new spots and changes to spots you already have. Take note of where moles and freckles are so you notice if a new one appears. You don't need to memorize every detail — just get a sense of what your skin normally looks like. That way, when something changes, you'll notice.
If you find a spot that fits the ABCDE rule or that simply looks different and concerns you, write down when you noticed it and make an appointment with a dermatologist. Bring a photo if you can — it helps the doctor see whether the spot has changed since you first saw it.
When to see a dermatologist
See a dermatologist if you notice a new spot, a spot that's changing in size or color, a spot that itches or bleeds, or any mark that looks different from your other moles and freckles. You don't need to wait for it to get worse — early is better.
If you have a lot of moles, fair skin, a family history of skin cancer, or a history of sunburns, dermatologists often recommend a full-body skin check once a year. Some people with higher risk see a dermatologist more often. Your regular doctor can refer you to a dermatologist, or you can find one through your insurance company's website or a local hospital.
Getting an appointment usually takes a few weeks, so don't delay if you're concerned about a spot. Many dermatology offices keep same-week or next-week slots open for new concerning marks.
What happens after a diagnosis
If a biopsy shows skin cancer, your dermatologist will discuss treatment options. For basal cell and squamous cell carcinomas, removal is often the main treatment — the doctor removes the cancer and a margin of healthy skin around it. This is usually done in the office under local anesthesia.
Melanoma treatment depends on how deep it goes and whether it has spread. Early melanomas are often removed surgically. More advanced cases may involve additional treatments, which your dermatologist or an oncologist (cancer specialist) will explain.
After treatment, you'll need follow-up visits to make sure the cancer doesn't return and to watch for new skin cancers. Your doctor will tell you how often to come back and what to watch for at home.
Frequently Asked Questions
Can a dermatologist tell if a spot is cancer just by looking at it?
A dermatologist can often tell a spot looks suspicious based on appearance and experience, but the only way to know for certain is a biopsy. Even experienced doctors can't diagnose cancer by sight alone — the microscope is needed to see cancer cells.
Does a biopsy hurt?
No. The dermatologist numbs the area with a local anesthetic before taking the sample, so you feel pressure but not pain. The procedure takes a few minutes, and the numbing medicine wears off within an hour or two.
If I had one skin cancer, will I definitely get another?
Not necessarily, but your risk is higher than someone who has never had skin cancer. That's why dermatologists recommend yearly skin checks and careful sun protection if you've had one. Many people have one skin cancer and never have another.
What's the difference between a mole and skin cancer?
Most moles are benign and don't change. Skin cancer usually appears as a new spot or a spot that's changing in size, shape, or color. If you're unsure whether a spot is a mole or something else, a dermatologist can tell you in one visit.
How long does it take to get biopsy results?
Most labs return results within a week. Your dermatologist's office will call you with the results and schedule a follow-up visit to discuss what they mean and what comes next.