What to look for on your skin

Skin cancer often shows itself as a change on your skin—a new spot, a spot that looks different than it did before, or a sore that does not heal. The most common warning signs are asymmetry (one half does not match the other), irregular borders, color variation within a single spot, a diameter larger than a pencil eraser, and evolution (the spot changes size, shape, or color over weeks or months). Not every change means cancer, but any spot that is new, growing, bleeding, itching, or looks unusual warrants a conversation with a doctor.

The three main types of skin cancer—basal cell carcinoma, squamous cell carcinoma, and melanoma—can look different from each other. Basal cell carcinoma often appears as a shiny bump or a sore that bleeds and scabs over repeatedly. Squamous cell carcinoma may look like a scaly patch, a raised bump, or a sore with a crusty center. Melanoma is the most dangerous type and is most likely to spread; it often has the asymmetry, irregular borders, and color variation described above, though it can also appear as a dark, flat spot.

Key Takeaways

  • Any spot that is new, growing, bleeding, itching, or changing shape or color should be checked by a doctor or dermatologist.
  • The ABCDE rule—asymmetry, border irregularity, color variation, diameter larger than a pencil eraser, and evolution—helps identify spots that need medical attention.
  • Basal cell and squamous cell carcinomas are more common and often slower-growing, but melanoma is more likely to spread and requires faster action.
  • A dermatologist can examine a spot in person and take a biopsy (a small tissue sample) if needed to confirm whether it is cancer.

When to see a doctor about a spot

You do not need to wait for a spot to meet all five ABCDE criteria before scheduling an appointment. If a spot is new and you have not seen it before, or if an existing spot has changed in any way over the past few weeks or months, that is reason enough to have it checked. The same goes for any sore that does not heal within a few weeks, any spot that itches or bleeds without injury, or any spot that simply looks wrong to you.

Your primary care doctor can examine a spot and refer you to a dermatologist if there is concern. A dermatologist is a doctor who specializes in skin and can often tell whether a spot is cancerous just by looking at it, though the only way to know for certain is a biopsy—a procedure in which the doctor removes a small sample of skin and sends it to a lab for testing. This is a quick office procedure that takes minutes.

Spots that are usually not cancer

Many skin changes are harmless. Age spots (also called liver spots) are flat, brown patches that appear as you get older, usually on the hands, face, or arms. They have even color and regular borders and do not change. Moles are common and usually benign; most people have between 10 and 40 moles by adulthood. A mole that has been the same size, shape, and color for years is almost certainly not cancer.

Seborrheic keratosis is a common, noncancerous growth that looks waxy or scaly and can be brown, black, or tan. Freckles are small, flat, brown spots that are harmless. Warts are caused by a virus and have a bumpy texture. If you are unsure whether a spot is harmless or worth checking, a dermatologist can tell you in one visit and put your mind at ease.

Risk factors that increase your chances

Certain factors make skin cancer more likely. Sun exposure is the biggest one—the more time you spend in the sun without protection, the higher your risk. Fair skin, light hair, and light eyes increase risk because there is less melanin (the pigment that protects skin from UV damage). A personal history of sunburns, especially severe ones in childhood, raises risk. A family history of skin cancer also matters; if a parent or sibling has had skin cancer, your risk is higher.

Weakened immune system, certain medications (including some that make you more sun-sensitive), and a large number of moles also increase risk. Age matters too—melanoma can occur at any age, but basal cell and squamous cell carcinomas are more common as you get older. If you have any of these risk factors, paying attention to your skin and checking it regularly becomes more important.

How to check your own skin regularly

A skin self-exam takes about 10 minutes and can be done monthly. Use a mirror in a well-lit room, and check your entire body—front, back, sides, and the soles of your feet and between your toes. Look at your scalp by parting your hair in sections. If you have a partner, ask them to check your back and the back of your neck, which are hard to see on your own.

Take note of where your moles and spots are and what they look like. If you find a new spot or notice that an existing one has changed, write down the date and take a photo if you can. This record helps you and your doctor track changes over time. You do not need special tools or apps—a mirror, good light, and your own eyes are enough.

What happens after you see a doctor

If your doctor thinks a spot might be cancer, they will likely take a biopsy. The doctor numbs the area with a local anesthetic, removes a small sample of skin (either by shaving, punching, or excising), and sends it to a pathology lab. Results usually come back within a week or two. If the biopsy shows cancer, your doctor will discuss treatment options, which depend on the type and stage of cancer.

For basal cell and squamous cell carcinomas caught early, treatment is often straightforward and can be done in an office setting. Melanoma requires more aggressive treatment and may involve surgery, radiation, or other therapies. The earlier skin cancer is caught, the simpler the treatment and the better the outcome. This is why checking your skin regularly and seeing a doctor about any change matters.

Frequently Asked Questions

Can you have skin cancer without seeing a spot?

Skin cancer almost always shows up as a visible change on the skin. If you have not noticed any new spots or changes to existing ones, the risk is very low. That said, if you have risk factors like fair skin or heavy sun exposure, regular skin checks by a dermatologist can catch early changes you might miss on your own.

Does a changing mole always mean cancer?

No. Moles can change slightly over time, especially in younger people. However, rapid changes—a mole that grows, changes color, or becomes itchy or bleeding within weeks or a few months—should be checked by a doctor. Slow, gradual changes over years are less concerning, but any change worth noticing is worth mentioning to a dermatologist.

What if I find a spot but my doctor says it looks fine?

If your doctor has examined the spot in person and is not concerned, that is reassuring. You can ask them how often to check it and when to come back if it changes. If you remain worried or the spot continues to change, you can ask for a second opinion or a referral to a dermatologist.

Is a biopsy painful?

No. The doctor injects a local anesthetic to numb the area before removing the sample, so you should feel pressure but not pain. The procedure takes a few minutes, and the numbing medication wears off within a few hours. Some people have mild soreness afterward, similar to a small cut.

Can you get skin cancer from a sunlamp or tanning bed?

Yes. Tanning beds and sunlamps emit ultraviolet (UV) radiation that damages skin cells and increases skin cancer risk. The risk is especially high if you use them regularly or start using them before age 35. Avoiding tanning beds is one of the most direct ways to lower your skin cancer risk.