How to Know If a Mole Is Dangerous

The average person has 10-40 moles, also known as nevi, and most are harmless. But in rare cases, a new or existing mole can develop into melanoma, a serious form of skin cancer.

In addition to regular skin cancer screenings with our team at Shady Grove Dermatology, performing at-home self-exams is a proactive habit that could make a lifesaving difference. Here, learn how to identify the early warning signs of a dangerous mole.

Understanding moles: What is normal?

Moles are common growths that occur when pigment-producing cells, called melanocytes, grow in clusters instead of spreading evenly throughout the skin. They can occur anywhere on your body, be flat or raised, smooth or textured, and range from your natural skin color to a deeper shade of brown or black.

Some people are born with moles, known as congenital nevi, but most develop them during childhood and adolescence. Each mole has an average lifespan of about 50 years, after which they may begin to fade, flatten, or disappear.

The critical warning signs

Because moles can be so diverse across different skin types and individuals, it can be difficult to know what’s normal and when to seek medical guidance. If you have a spot you’re unsure about, the ABCDE method can help you identify concerning characteristics:

• A for asymmetry — half of the mole looks different from the other if you draw an imaginary line down the middle
• B for border — the edges are irregular, undefined, or ragged, rather than smooth
• C for color — the mole contains various shades of color, which may include patches of brown, black, red, blue, white, or gray
• D for diameter — the spot is larger than a pencil eraser, although melanomas can also be very small
• E for evolving — the mole noticeably changes in size, shape, or color over time

But atypical moles aren’t always cancerous. Around 70% of melanomas develop not from existing moles, but as new spots on the skin. Pay attention to new moles that appear after the age of 30, especially if they match any of the ABCDE criteria.

And don’t forget the warning signs you can feel. Itchy, bleeding, or painful moles also warrant a closer look by our team. 

How to perform a skin self-exam

We recommend setting aside time for a skin self-exam at least once a month. 

Familiarizing yourself with what’s normal for your body allows you to quickly notice any new moles, changes to existing ones, and any other unusual developments. Skin cancer doesn’t always look like a mole; it may appear as a scaly patch, an open sore, or a firm bump.

To ensure a thorough, comfortable self-exam, find a private, well-lit room with a full-length mirror and a chair. Keep a small hand mirror nearby for examining hard-to-see areas on your back.

Be methodical: Start with your scalp, using a comb or blow-dryer to part your hair for a clear view of the skin. Continue down the rest of your body, front and back, focusing on areas you might otherwise miss, like the spaces between your toes or the soles of your feet.

Your next steps

If your at-home check reveals anything worrisome, make an appointment with our team. A professional diagnosis is the only way to confirm or rule out skin cancer. 

We may take a biopsy (tissue sample) for lab testing to determine whether skin cancer is present. Fortunately, both melanoma and non-melanoma skin cancers are highly treatable when caught early. 

We also offer professional mole removal for benign spots that cause cosmetic concern or physical irritation.

Do you have concerns about a new or changing mole? Call or click to schedule a consultation with us at Shady Grove Dermatology in Rockville, Maryland.