Just a Mole or Melanoma? How to Tell the Difference

Moles are extremely common skin growths that happen when pigment cells called melanocytes, which give the skin its color, grow in clusters. Chances are, you probably have a few (or more). Most people do. While most moles are harmless, some moles or other unusual areas on the skin can be a type of skin cancer called melanoma. Early detection of melanoma allows your doctor to treat cancer before it spreads to the lymph nodes and other parts of your body, such as the liver, lungs, or brain.

Because melanoma can appear in different forms, it can be tricky to detect. But being aware of the warning signs can help you tell the difference between common moles and melanoma and know when to see your doctor.

What Common Moles Look Like

Usually, common moles appear on parts of the body above the waist that are frequently exposed to the sun. Moles often start to appear in later childhood years, and new moles can continue to pop up until around age 40. Later in adulthood, common moles often start to fade.

Most common moles have similar characteristics:

• Distinct edge
• Even tan, brown, or pink color
• Less than ¼ inch across, about the size of a pencil eraser
• Oval or round shape
• Raised or flat
• Smooth surface

It’s important to pay attention to any changes in moles. Although rare, common moles can turn into melanoma.

Understanding Melanoma

Melanoma is the most serious type of skin cancer, as it is the most likely to spread if not detected and removed. Melanoma forms when melanocytes grow uncontrollably, and it can occur on any area of the skin. For lighter-skinned people, melanomas most often form on the back and chest in men, while in women they are most common on the legs. Melanoma also develops on the face and neck.

Still, some melanoma types can occur in much less common areas not exposed to the sun, especially for people with darker skin tones. These types include:

• Acral lentiginous melanoma. This forms under the nails, on the soles of the feet, or on the palms of the hands. It can cause a dark streak in the nail or dark areas on the feet or palms.
• Mucosal melanoma. This occurs in the nose, mouth, or genitals and may look like dark spots or irregular patches.
• Uveal melanoma. This develops in the eye and can appear as a dark spot in the iris.

About 20% to 30% of melanomas form in existing moles, but the majority develop on areas of “normal” skin.

The ABCs of Melanoma Detection

Because early detection of melanoma greatly increases survival rates, develop a habit of checking your skin from head to toe once per month. Look for any changes in moles or other areas of concern.

The ABCDE rule can help you remember what to be aware of:

• A: Asymmetry. Common moles are usually symmetrical, but melanomas are often asymmetrical, which means the two halves don’t match.
• B: Border. The borders of a melanoma are often ragged or notched, while common moles tend to have smoother, more even borders.
• C: Color. The color of a common mole is usually even. A melanoma may contain different shades of brown, black, or tan, or sometimes red, white, pink, or blue.
• D: Diameter. A mole that is larger than ¼ inch across is a sign of melanoma (although some melanomas can be smaller than this).
• E: Evolving. If an existing mole changes in size, shape, or color or new signs appear, see your doctor.

Other warning signs to watch for include:

• A mole that becomes dry, scaly, hard, or lumpy
• A mole that starts to hurt, itch, bleed, or ooze
• A mole that looks distinctly different from the others around it (an “ugly duckling”)
• New swelling or redness past the border of a mole
• Pigment spreading beyond the border of a mole or spot into the surrounding skin
• A sore that doesn’t get better

Not every melanoma follows any or all of these signs, so see your doctor about any skin changes that concern you.

Know Your Risk Factors

While anyone can develop melanoma, several risk factors can put you at higher risk. Some are factors you can control, which means changing them can reduce the risk of melanoma.

Risk factors for melanoma include:

• Exposure to ultraviolet (UV) light. This is one of the biggest risk factors for melanoma. UV rays cause damage inside skin cells, which can lead to skin cancer. Spending time in sunlight without protecting your skin is the main way people are exposed to UV rays, but you can also develop melanoma from using tanning beds or sun lamps.
• Family history of melanoma. Having a parent, sibling, or child who has had melanoma puts you at higher risk for the condition.
• Light skin tone, hair, and eye color. People with lighter skin tones are much more likely to develop melanoma than those with darker skin tones. Additionally, having green or blue eyes, red or blond hair, or skin that tends to burn or freckle increases your risk.
• Many moles or atypical moles (called dysplastic nevi). If you have a lot of moles, you are more likely to develop melanoma. In addition, if you have a mole that is an abnormal shape or color, there is a small chance it could turn into a melanoma.

Tips to Prevent Melanoma

Many risk factors for melanoma can’t be changed, but you can take steps to help lower your risk:

• Avoid artificial sources of UV rays. Don’t use tanning beds or sun lamps.
• Check your skin regularly. Examine yourself for changes in moles or other skin abnormalities once a month and have an exam by a dermatologist every year.
• Protect yourself from the sun. When spending time outdoors, use sunscreen with a minimum SPF 30 on all exposed skin, and seek shade when possible. You can also wear a long-sleeved shirt and pants, a wide-brimmed hat, and sunglasses that block UV rays.

If you notice any skin changes that concern you, don’t wait to see your doctor. Find a provider.