Melanoma has distinct visual warning signs you can spot on your own skin, and catching it early makes an enormous difference. When melanoma is still localized to the skin, the five-year survival rate is 97.6%. Once it spreads to distant parts of the body, that number drops to 16.2%. Knowing what to look for, and actually looking, is the single most important thing you can do.
The ABCDE Rule for Suspicious Moles
Most melanomas start as changes in existing moles or as new spots on the skin. The National Cancer Institute uses a five-letter system to describe features of early melanoma:
- Asymmetry: One half of the mole doesn’t match the other half in shape.
- Border: The edges are ragged, notched, or blurred rather than smooth. Pigment may spread into the surrounding skin.
- Color: The color is uneven. You might see shades of brown, black, and tan mixed together, or patches of white, gray, red, pink, or blue.
- Diameter: Most melanomas are larger than 6 millimeters across (roughly 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.
You don’t need all five features to be concerned. Any single one, especially a mole that is clearly evolving, is worth getting checked. The “E” is arguably the most important letter. A spot that looked the same for years and suddenly starts changing deserves attention regardless of what it looks like.
The Ugly Duckling Sign
There’s another approach that works alongside the ABCDE rule and is sometimes even more intuitive. Most of your moles tend to resemble each other. They share a similar color, size, and shape because they developed under the same genetic and sun-exposure conditions. The “ugly duckling” is any mole that looks noticeably different from the rest of the moles on your body.
Researchers at Harvard Health found that dermatologists who used the ugly duckling approach were able to identify melanomas accurately while reducing the number of unnecessary biopsies. In practical terms, this means scanning your skin and asking: does any one spot stand out as clearly unlike the others? A dark mole surrounded by lighter ones, a large mole among small ones, or a reddish spot in a field of brown moles are all ugly ducklings worth investigating.
Melanomas That Don’t Look Like Melanomas
Not every melanoma follows the classic rules. Two types in particular are easy to miss.
Nodular Melanoma
Nodular melanoma grows vertically into the skin rather than spreading outward, so it often skips the asymmetry and irregular borders that define early melanoma. Instead, look for three features known as the EFG criteria: a spot that is elevated above the skin surface, feels firm to the touch, and is growing rapidly, with noticeable changes over days or weeks rather than months. These tend to appear as dome-shaped bumps and can be dark or skin-colored.
Amelanotic Melanoma
Amelanotic melanoma contains little or no pigment, which means it doesn’t look dark or brown the way most people expect melanoma to look. It typically shows up as a pink to red flat spot, bump, or nodule. Because it resembles so many other skin conditions, it’s frequently misdiagnosed or caught at a later stage. If you have a new pink or reddish spot that doesn’t heal, doesn’t match a known condition like eczema, and keeps growing, treat it with the same suspicion you’d give a dark mole.
Melanoma on Darker Skin
Melanoma can develop on any skin tone, but it shows up in different places depending on your complexion. In people of color, the most common type is acral lentiginous melanoma, which develops on the palms of the hands, soles of the feet, and under the nails. According to Memorial Sloan Kettering Cancer Center, the main sign is a black or brown discoloration on the sole or palm that looks like a bruise or stain but grows over time.
Under the nails, this type of melanoma appears as dark vertical streaks or discolorations running along the nail bed. As it progresses, it can cause cracks and breaks in the nail. It’s often mistaken for a fungal infection or a blood blister from an injury. Because these locations aren’t typically associated with skin cancer, melanoma in people with darker skin is frequently diagnosed later, when treatment is harder.
How to Check Your Own Skin
The American Academy of Dermatology recommends checking your skin regularly. You don’t need special equipment, just a full-length mirror, a hand mirror, and good lighting. Work through your body systematically:
- Stand in front of the full-length mirror and examine your body front and back, then raise your arms and check both sides.
- Bend your elbows and look at your forearms, underarms, fingernails, and palms.
- Check the backs of your legs, the spaces between your toes, your toenails, and the soles of your feet.
- Use a hand mirror to examine the back of your neck, your scalp (parting your hair as you go), your back, and your buttocks.
The scalp, soles of the feet, spaces between toes, and nail beds are the areas people skip most often, and they’re exactly where some melanomas hide. If you have a partner, ask them to check your back and scalp for you. Take photos of moles you want to track so you can compare them month to month. Changes that are hard to notice day to day become obvious in side-by-side photos taken a few weeks apart.
What Your Risk Profile Looks Like
Some people need to be more vigilant than others. Your risk increases with UV exposure, particularly a pattern of intense, intermittent sun exposure that causes sunburns. Sunburns during childhood are especially linked to melanoma developing on the chest, back, and legs later in life.
Having many moles raises your risk simply by numbers. The chance of any single mole becoming cancerous is very low, but someone with a large number of moles, particularly irregular or large ones, has a greater overall chance. About 1 in 10 people with melanoma have a family history of the disease. If a parent, sibling, or child has had melanoma, your risk is higher, whether from shared genetics, shared sun habits, or lighter skin tones that run in your family.
What Happens if a Spot Looks Suspicious
A dermatologist will visually examine the spot, often using a dermatoscope (a handheld magnifying device with a light) to see structures beneath the skin surface that aren’t visible to the naked eye. If the spot looks concerning, the next step is a biopsy, which is the only way to confirm or rule out melanoma.
For a suspected melanoma, the preferred approach is an excisional biopsy, where the entire suspicious area is removed along with a small margin of normal skin. This is done under local anesthesia, so you’ll feel pressure but not pain. Smaller or less suspicious spots may be sampled with a punch biopsy, which removes a small cylinder of skin about the size of a pencil eraser, or a shave biopsy, which takes a thin layer from the surface. The sample goes to a lab, and results typically come back within one to two weeks.
If the biopsy confirms melanoma, the stage and thickness of the tumor determine what comes next. Early, thin melanomas are often fully treated by the biopsy itself or a slightly wider excision. Thicker or more advanced melanomas require additional evaluation and treatment. The key takeaway is that a biopsy is a quick, low-risk procedure, and getting one early is far better than watching a spot change for months while hoping it’s nothing.