The short answer
Most moles are harmless and stay the same for years. The changes worth checking follow the ABCDE guide: Asymmetry, Border irregularity, Color variation, Diameter larger than a pencil eraser, and Evolving (changing). A mole that changes, itches, or bleeds is worth showing a doctor.
Most moles are harmless and do not change.
The ABCDE guide flags moles worth checking: Asymmetry, Border, Color, Diameter, Evolving.
A mole that changes, itches, or bleeds is worth a doctor's look.
A new or changing spot in adulthood deserves attention.
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The full explanation.
The simple version
Nearly everyone has moles, and the great majority are harmless and stay the same for years. What matters is change: a mole that is growing, changing color or shape, or behaving differently is the kind worth checking.
The ABCDE guide
Dermatologists use ABCDE to describe moles worth checking: Asymmetry (one half unlike the other), Border that is ragged or blurred, Color that is uneven or has several shades, Diameter larger than a pencil eraser (about 6 mm), and Evolving — any change in size, shape, color, or symptoms over time.
Other changes worth noticing
Besides ABCDE, watch for a mole that itches, bleeds, crusts, or does not heal, or a brand-new dark spot appearing in adulthood. A spot that looks different from your other moles — sometimes called the ugly duckling — is also worth showing a doctor.
When to see a doctor
See a doctor or dermatologist about any mole that is changing, new, itching, or bleeding, or that stands out from your others. Skin cancer, including melanoma, is very treatable when caught early, so checking is worthwhile.
Words to know
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Common questions
▸Are most moles cancer?
No. Most moles are harmless and stay the same for years. It is changing or unusual moles that are worth checking.
▸What is the ABCDE guide?
It flags moles worth checking: Asymmetry, Border irregularity, Color variation, Diameter over about 6 mm, and Evolving (any change over time).
▸What changes should I watch for?
A mole that grows, changes color or shape, itches, bleeds, or does not heal — or a new dark spot in adulthood — is worth a doctor's look.
▸How is skin checked?
A doctor or dermatologist can examine the skin and, if needed, take a small sample (biopsy) of a suspicious mole.
Questions to ask your doctor
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