Most people have moles somewhere on their body, and the vast majority are harmless. They may have been there since childhood or appeared gradually over the years without causing any problems.
But sometimes, a new or changing spot on the skin deserves closer attention.
Certain changes can be warning signs of melanoma, a serious form of skin cancer. Knowing what to look for can help you recognize when it’s time to have a dermatologist examine a mole.
The ABCDE rule
Dermatologists commonly use the ABCDE rule to describe features that may warrant medical evaluation.
A — Asymmetry
Imagine drawing a line through the middle of the mole. If one half looks noticeably different from the other, it may be worth having it checked.
B — Border
Pay attention to the edges. A typical mole often has relatively smooth, clearly defined borders.
A mole with irregular, blurred, scalloped or poorly defined edges can be more concerning.
C — Color
Many harmless moles are fairly uniform in color.
A spot containing several colors—such as different shades of brown, black, red, white or blue—should receive closer attention, particularly if its appearance has changed.
D — Diameter
Larger moles can deserve additional attention. A commonly used reference is about 6 millimeters, roughly the size of a pencil eraser.
However, size alone doesn’t determine whether a mole is dangerous. Melanomas can sometimes be smaller.
E — Evolving
This may be one of the most important warning signs.
A mole that begins changing in size, shape, color or elevation—or starts behaving differently from your other moles—shouldn’t simply be ignored.
Don’t ignore itching, bleeding or crusting
Appearance isn’t the only thing that matters.
A skin lesion that repeatedly itches, hurts, bleeds, becomes crusty or develops a sore that doesn’t heal deserves medical attention.
Bleeding after accidentally scratching a normal mole doesn’t automatically mean cancer. The concern is a spot that repeatedly bleeds or changes without an obvious explanation.
Watch for the “ugly duckling”
Another useful concept is known as the ugly duckling sign.
Most of a person’s normal moles tend to resemble one another. If you have one spot that looks dramatically different from everything else on your skin, it’s worth paying attention to—even if it doesn’t perfectly match every ABCDE characteristic.
A changing mole doesn’t automatically mean cancer
This is important.
Finding an unusual mole does not mean you have melanoma. Many benign skin conditions can produce spots that look unusual.
And a photograph on the internet cannot reliably determine whether a particular mole is cancerous.
A dermatologist can examine the lesion closely and, when necessary, perform a biopsy to determine exactly what it is.
Check areas you don’t normally see
When looking over your skin, don’t focus only on your arms and face.
Suspicious lesions can occur on the back, scalp, behind the ears, legs, between the toes and other areas that are easy to overlook.
Using a mirror—or asking someone you trust to look at difficult-to-see areas—can make a skin check more complete.
When should you see a doctor?
Consider arranging a medical evaluation if you discover:
- A new mole that looks unusual
- A mole that is noticeably changing
- An irregular or multicolored spot
- A lesion that repeatedly bleeds, itches or crusts
- A sore that doesn’t heal
- One mole that looks very different from all your others
If something on your skin concerns you, you don’t need to wait until it matches every warning sign before asking a professional to look at it.
The bottom line
Most moles are completely harmless. But new, unusual or changing spots shouldn’t be ignored.
Learning the ABCDE warning signs and occasionally paying attention to your skin can help you recognize changes earlier.
And when you’re unsure, don’t try to diagnose a suspicious mole from a picture online. Have it examined by a qualified healthcare professional.
When it comes to unusual changes in your skin, getting an expert opinion is far better than guessing.
