The vast majority of moles are benign and stay that way. The point of surveillance is not to worry about every naevus, but to spot the one that changes or stands out. Caught early, melanoma is highly treatable: a few simple markers tell you what to watch for — and when to seek advice.
Melanoma can develop from an existing mole or, more often, appear on previously healthy skin. Its prognosis depends heavily on how early it is diagnosed: found at an early stage, it is most often treated by simple excision. That is what makes regular self-examination — and, for people at risk, structured medical follow-up — so worthwhile.
No single criterion is conclusive on its own; it is their combination — and above all evolution — that should prompt a medical opinion.
In any one person, moles tend to look alike. A lesion that does not resemble the others — darker, larger, different to the touch — deserves particular attention, even if it ticks no ABCDE box. The “ugly duckling” sign complements the ABCDE rule.
Some signals warrant a consultation without waiting for your next self-exam: a lesion that bleeds without trauma, crusts over, itches persistently or becomes painful, a sore that does not heal, or a new pigmented lesion appearing in adulthood, particularly after 40. A pigmented streak on a nail, or a spot spreading on a mucous membrane, should also be shown to a doctor.
Ideally every three months, in a well-lit room, with a full-length mirror and a hand mirror: face, scalp (using a hairdryer to part the hair), neck, chest, back, arms, armpits, hands and nails, legs, soles of the feet and between the toes, genital areas. Taking dated photos of notable lesions helps objectify change — which is, at an individual scale, the principle that mole mapping systematises with standardised images compared over time.
Seek advice for any change persisting beyond a few weeks, any warning sign described above, or simply when in doubt. If you combine risk factors — fair skin, numerous naevi, a personal or family history of melanoma, severe childhood sunburns — discuss it with your doctor: regular follow-up can be organised.
To have your moles examined as part of a skin mapping:
Book an appointment →Sources & further reading: French National Cancer Institute (e-cancer.fr), French Society of Dermatology (dermato-info.fr), Santé publique France. These markers are general-public guidance tools; only a medical examination can provide a diagnosis.