March 14, 2024/Skin Care & Beauty

Is That Mole Cancerous?

The size, shape and color of moles may offer clues that point to melanoma

Gloved hands of healthcare provider examining moles on a back

Sometimes, you look at a mole and think, “That doesn’t look quite right.” Don’t ignore those suspicions. There’s a chance what you see may be a sign of melanoma, a dangerous form of skin cancer.


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So, that leads to an obvious question: How can you tell if a mole might be cancerous? It turns out there are definite hints visible to the naked eye.

Dermatologist Christine Poblete-Lopez, MD, explains how to spot potential trouble.

Warning signs of cancerous moles

Moles aren’t unusual. In fact, most adults have between 10 and 40 of them scattered around their bodies. These so-called “beauty marks” are typically harmless and nothing to worry about either.

But the following variations may indicate the development of melanoma and deserve a closer look by a healthcare professional.

The ABCDEs of skin cancer

Certain characteristics of a mole can offer hints when it comes to melanoma. Dr. Poblete-Lopez says the rule of thumb in dermatology is to consider the ABCDEs.

  • A = Asymmetry: Do you have a mole in which one half doesn’t match the other? If so, that asymmetry may spell trouble.
  • B = Border: A mole border that’s fuzzy, poorly defined, ragged or blurred should be considered a red flag. Ditto if you see a small notch or protrusion along the edge of a mole.
  • C = Color: Moles featuring two to three different shades of brown should be looked at a bit suspiciously. Moles colored blue, gray, red, black or white also may signal possible melanoma.
  • D = Diameter: Moles larger than 6 millimeters — roughly the size of the eraser atop a pencil — tend to be more worrisome. (That being said, melanomas also can be pinpoint in size.)
  • E = Evolution: Consider noticeable changes in a mole to the biggest warning sign of all. Concerns increase if a mole bleeds or begins to ooze with minimal trauma.

It’s important to note that hitting on any of the ABCDE criteria doesn’t guarantee melanoma in a mole. But the indicators do signal an increased possibility of skin cancer.

A new mole

Nearly 70% of melanomas begin as a new mole, which is why any mole that randomly appears deserves your attention. (This is especially true if the new mole checks boxes on the ABCDE list noted above.)

To be clear, though, not all new moles are cancerous. Most are benign and nothing more than a new mark on your skin. But that doesn’t mean they should be ignored.


“It’s best to get new moles checked by your healthcare provider,” advises Dr. Poblete-Lopez.

Moles that itch

Moles can become itchy for a variety of reasons. It might be something as simple as dry or irritated skin, for example, or an allergic reaction to whatever laundry detergent you just picked up.

But there’s also a chance it could be a sign of melanoma, says Dr. Poblete-Lopez. Concerns increase if the mole bleeds or begins to ooze.

Bottom line? Get it looked at by a medical professional sooner rather than later.

An ‘ugly duckling’ mole

For someone with a lot of moles, healthcare professionals often look for atypical moles and so-called “ugly ducklings” that stand out and look different. These moles often check more of the ABCDE characteristics.

The good news? It’s extremely rare for the average atypical mole to transform into melanoma. The risk is estimated at 1 in 10,000.

But increased numbers of atypical moles on your body raise your skin cancer risk. If you have 10 or more atypical moles, you’re statistically 12 times more likely to eventually develop melanoma.

It’s common for people with atypical moles to see a dermatologist regularly to monitor them for changes. Magnifying devices are often used to check for abnormalities invisible to the naked eye.


“What we find under the microscope will guide how aggressive we’ll need to be in checking your moles,” explains Dr. Poblete-Lopez. “If you’ve got a higher chance of developing cancer based on what we see, we may suggest checkups every six months instead of every year or two.”

When to see a dermatologist

Early detection is key to treating melanoma. Dr. Poblete-Lopez recommends doing skin self-checks once a month. Use the time to look for new moles and examine existing moles for anything unusual. Talk to your healthcare provider about any concerning findings.

Regular visits to a dermatologist may be warranted if you’re at increased risk for developing melanoma. Risk factors include:

  • Numerous moles on your body.
  • A history of indoor tanning.
  • Fair skin or skin that easily burns, freckles or reddens.
  • A personal history of skin cancer.
  • A family history of melanoma.
  • Heavy sun exposure at work or play.
  • Lots of sunburns early in life.
  • Blue or green eyes.
  • Blonde or red hair.

Melanoma is one of the most common forms of cancer in the United States, representing 5% of all new cancer diagnoses. Case counts have been steadily rising for decades, too, reports the National Cancer Institute.

“The beauty of dermatology is that we can quickly see if there’s a problem on the surface and then do a skin biopsy, a simple in-office procedure,” reassures Dr. Poblete-Lopez. “We may be able to find anything that’s trouble early on.”

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