Checking for skin cancer starts with knowing what to look for and where to look. About 112,000 new melanoma cases will be diagnosed in 2026 alone, and roughly 2.2% of people will develop melanoma at some point in their lifetime. Non-melanoma skin cancers like basal cell and squamous cell carcinoma are far more common. The good news is that skin cancer is one of the few cancers you can spot with your own eyes, often before it becomes dangerous.
The ABCDE Rule for Melanoma
The most widely used framework for spotting melanoma is the ABCDE rule, developed by the National Cancer Institute. Each letter flags a specific warning sign in a mole or spot on your skin:
- 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. Pigment may seem to bleed into the surrounding skin.
- Color: The spot has uneven coloring. You might see a mix of black, brown, tan, white, gray, red, pink, or blue within the same lesion.
- Diameter: Most melanomas are larger than 6 millimeters across (about the size of a pencil eraser), though they can be smaller.
- Evolving: The mole has changed in size, shape, or color over the past few weeks or months. Any noticeable change is worth attention.
You don’t need all five features to be concerned. A single one, especially evolution, is enough reason to have a spot evaluated.
The Ugly Duckling Sign
The ABCDE rule works well when you’re examining a single mole in isolation. But there’s a complementary technique that’s just as useful: the ugly duckling sign. Most of your moles tend to look similar to each other. If one mole stands out from the rest, looking noticeably different in color, size, or shape, that’s the “ugly duckling,” and it deserves closer scrutiny. This approach is especially helpful for people with many moles, where evaluating each one individually would be overwhelming.
What Non-Melanoma Skin Cancers Look Like
Melanoma gets the most attention, but basal cell carcinoma is actually the most common skin cancer. It often appears as a slightly transparent or pearly bump on the skin. On lighter skin, this bump looks white or pink. On brown or Black skin, it may appear brown or glossy black. You might notice tiny blood vessels running across the surface, and the bump may bleed and scab over repeatedly.
Basal cell carcinoma doesn’t always look like a bump, though. It can also show up as a flat, scaly patch that slowly grows larger over time, or as a white, waxy area that looks like a scar but appeared without any injury. The hallmark of both basal cell and squamous cell carcinoma is a sore that won’t heal. If you have a spot that crusts, bleeds, heals partially, then opens again over weeks or months, that pattern itself is a red flag.
Squamous cell carcinoma can appear as thick, red patches on the skin and sometimes develops under fingernails or toenails, where it’s easy to miss.
How to Do a Full-Body Self-Exam
A thorough check takes about 10 minutes and requires a full-length mirror, a hand mirror, and good lighting. Start with your face, ears, and neck, then work your way down your arms, torso, legs, and feet. Use the hand mirror to check your back, the backs of your thighs, and your scalp.
The areas people skip are the ones where cancers grow undetected the longest. Check between your toes, where skin cancers can become aggressive because they’re so rarely noticed. Check your scalp, especially along your hair part, which gets consistent sun exposure. If you have thinning or lighter-colored hair, your scalp is particularly vulnerable. Check the palms of your hands and the soles of your feet. A rare but serious form called acral lentiginous melanoma forms in these areas and is the most common type of melanoma in people of color.
Your nail beds are another hidden spot. If you wear nail polish regularly, take it off periodically and examine your bare nails for dark streaks, discoloration, or changes in the nail structure.
Know Your Risk Level
Your skin’s natural response to sunlight is one of the strongest predictors of skin cancer risk. People whose skin burns easily and rarely tans are at the highest end of the risk spectrum. In studies using skin type scoring (which rates factors like burn tendency, tanning ability, and baseline skin darkness on a scale), white skin averaged a score of 8 out of 28, while Asian, Latino, and other skin types scored around 13 to 14, and Asian Indian and African American skin scored around 20.
Lower scores correlate with higher cancer risk from UV exposure, but higher scores don’t mean zero risk. Skin cancer occurs across all skin tones, and it’s often diagnosed later in people with darker skin because neither patients nor doctors expect it. If you have darker skin, pay particular attention to areas that don’t get much sun: palms, soles, nail beds, and mucous membranes.
Other factors that increase your risk include a history of sunburns (especially blistering burns in childhood), a large number of moles, a family history of melanoma, use of tanning beds, or a weakened immune system.
How Often to Check
There’s no universally mandated screening schedule. The U.S. Preventive Services Task Force currently says there isn’t enough evidence to recommend for or against routine clinical skin exams for the general population. That guidance applies to people with no symptoms and no history of skin cancer or precancerous lesions. It’s not a statement that screening is unhelpful; it reflects a gap in large-scale research, particularly for people with diverse skin tones.
In practice, most dermatologists recommend a monthly self-exam and an annual professional skin check if you have elevated risk factors. If you’ve had skin cancer before or are under surveillance for precancerous changes, your doctor will set a more frequent schedule. For everyone else, doing a self-exam once a month builds the habit of noticing change, which is ultimately what catches skin cancer early.
What Happens If You Find Something
If a spot looks suspicious, a dermatologist will examine it visually, often using a dermatoscope (a magnifying tool with built-in light). If they want a definitive answer, they’ll perform a biopsy, which means removing a small sample of skin to examine under a microscope.
There are three common biopsy types. A shave biopsy removes a thin surface layer with a blade. A punch biopsy uses a small circular tool to take a deeper, round sample. An excisional biopsy cuts out the entire lesion along with a margin of surrounding skin. The method depends on the size and location of the spot and how deep the concern goes. All three are done with local numbing and typically take just a few minutes. Results usually come back within one to two weeks.
Most biopsied spots turn out to be benign. But the point of checking regularly isn’t to diagnose cancer yourself. It’s to notice changes early enough that if something is wrong, it’s caught at a stage when treatment is straightforward and outcomes are excellent.