Moles vs. Melanoma: How to Tell the Difference and When to Stop Guessing
Most moles are completely harmless. But some are not and the difference is not always visible to the untrained eye. Understanding what a normal mole looks like, what changes to watch for, and when to see a dermatologist takes the guesswork out of an important question: is this something I need to worry about?
Here, Dr. Zaki Taher — Edmonton’s Board-Certified Dermatologist — breaks down what you need to know.
What Is a Normal Mole?
A mole — medically referred to as a melanocytic nevus — is a common skin growth that develops when melanocytes (pigment-producing cells) cluster together rather than spreading evenly through the skin. Most people have between 10 and 40 moles on their body, and the majority develop before the age of 50.
Characteristics of a normal, benign mole:
- Uniform colour — typically a single shade of tan, brown, or dark brown
- Symmetrical shape — both halves match if divided down the middle
- Smooth, well-defined edges
- Stable size — generally smaller than 6mm in diameter
- Flat or slightly raised surface
- No bleeding, itching, or crusting
Normal moles can fade or disappear over time, and some will gradually become raised with age. Neither of these changes is inherently concerning, but any rapid or unexplained change warrants a professional evaluation.
What Are Atypical Moles (Dysplastic Nevi)?
Atypical moles — also called dysplastic nevi — are moles that look slightly abnormal but are not yet cancerous. They tend to be larger, with irregular borders, uneven colouring, or a mixture of pink, brown, and red tones. Having several dysplastic nevi is associated with a higher lifetime risk of developing melanoma.
Important: having atypical moles does not mean you have melanoma or will develop it. It simply means your skin warrants closer monitoring. A dermatologist can assess the degree of atypia and establish an appropriate surveillance schedule.
The ABCDE Rule: Your Starting Point for Self-Checks of Your Moles
The ABCDE rule is the most practical tool for evaluating moles at home. Run through it during monthly self-examinations:
A — Asymmetry: One half does not match the other when you mentally draw a line through the middle.
B — Border: The edges are blurry, jagged, notched, or poorly defined.
C — Colour: Multiple shades of brown, black, red, white, or blue appear within the same lesion.
D — Diameter: The lesion is larger than 6mm — about the size of a pencil eraser. Melanoma can be smaller when first detected.
E — Evolving: Any change in size, shape, colour, texture, or behaviour (new bleeding, itching, crusting) should be evaluated.
If any mole or lesion triggers concern on even one of these criteria, book an appointment with a dermatologist. You do not need to tick all five boxes to seek professional advice.
Signs That a Mole May Be Melanoma
Beyond the ABCDE rule, additional warning signs include:
- A new dark streak under a fingernail or toenail
- A mole or lesion that bleeds without trauma or injury
- A sore that does not heal over several weeks
- A shiny, firm nodule that was not previously present
- A lesion that looks dramatically different from your other moles — sometimes called the “ugly duckling” sign
It is also worth noting that not all melanomas arise from existing moles. Approximately 30 percent of melanomas develop in previously normal-appearing skin.
Not sure about a mole? Stop guessing. At Lucere Dermatology & Laser Clinic, Dr. Zaki Taher provides expert mole evaluations using dermoscopy for Edmonton patients. First consultation is complimentary. Book at lucereskin.com or call 780-461-1188.
What Happens at a Professional Mole Check?
A professional mole check at Lucere Dermatology involves a thorough, full-body skin examination conducted by Dr. Zaki Taher using dermoscopy — a non-invasive tool that magnifies the skin up to tenfold and allows detailed visualization of pigmented structures beneath the surface.
During your appointment, Dr. Taher will:
- Examine all moles and lesions, including those in hard-to-see areas like the scalp, back, between toes, and under nails
- Assess each lesion using dermoscopy for features not visible to the naked eye
- Flag any lesions requiring a biopsy for pathological analysis
- Provide personalized recommendations for monitoring and follow-up
If a biopsy is recommended, a small tissue sample is removed — a quick, minimally uncomfortable procedure — and sent to a pathology lab for definitive analysis.
How Often Should You Have a Mole Check?
The Canadian Dermatology Association recommends annual professional skin examinations for adults. Higher-risk patients — those with a personal or family history of skin cancer, a high number of moles, or significant past UV exposure — may benefit from more frequent monitoring.
In between professional checks, monthly self-examinations are strongly encouraged. Take note of any new moles or lesions, and document changes using photographs taken in consistent lighting.
What Is Mole Mapping?
Mole mapping is a full-body photographic documentation service that allows dermatologists to track moles over time. High-resolution images are taken at each visit, creating a visual baseline that makes changes easier to detect at subsequent appointments. For patients with a high number of moles or elevated melanoma risk, mole mapping provides an added layer of surveillance and peace of mind.
Frequently Asked Questions: Moles & Melanoma
Can moles turn into melanoma?
Yes, though most moles never do. Melanoma can develop from an existing mole or appear as a new lesion in normal skin. Regular self-checks and annual professional skin exams are the best way to catch concerning changes early.
Is it normal for moles to change during pregnancy?
Hormonal changes during pregnancy can cause moles to darken or enlarge slightly. While this is often benign, any changes to moles during pregnancy should be evaluated by a dermatologist to rule out melanoma.
Should I be worried about a mole I have had since childhood?
Congenital moles — those present at birth or in early childhood — should be monitored throughout life, particularly larger ones. Most remain benign, but annual evaluations by a dermatologist are recommended, especially for moles with any atypical features.
Does removing a mole hurt?
Mole removal at Lucere is typically performed under local anesthetic, making the procedure comfortable for patients. Depending on the mole’s characteristics, removal methods include excision, shave removal, or laser treatment. Dr. Taher will recommend the most appropriate approach based on your specific situation.