The ABCDE of pigmented lesions !

Sign

Five features of a mole (asymmetry, border, colour, diameter and evolution) that raise suspicion of melanoma and call for assessment.

Updated 2026-11-01

See it in 3D: Skin

What it is

The ABCDE is a screening rule for deciding which pigmented lesion deserves a closer look for possible melanoma. Each letter is a feature: Asymmetry, irregular Border, varied Colour, Diameter over 6 mm and Evolution (change). It does not diagnose; it selects lesions for dermoscopy or biopsy. The E (change over time) is the most valuable feature.

The anatomy it tests

Melanoma arises from the melanocytes of the epidermal basal layer, which make melanin.
Disordered growth gives irregular pigment (C) and asymmetric spread (A, B); it first spreads sideways, then invades down into the dermis.
Invasion depth (Breslow thickness), measured on biopsy, is the main prognostic factor, which is why finding it while thin matters.

How to elicit it

Examine the whole skin in good light, including scalp, soles, palms, nails, web spaces and genitals.
Ask whether any mole is new, has changed in size, shape or colour, itches, bleeds or crusts.
A: draw an imaginary line through the centre of the lesion and compare whether the two halves match in shape and colour.
B: look at the border: irregular, notched, blurred, or pigment fading into the surrounding skin.
C: count the shades: more than one colour (brown, black, red, white, grey or blue) is suspicious.
D: measure the longest diameter with a ruler; over 6 mm is suspicious, though smaller melanomas exist.
E: compare with earlier photos or records and look for the lesion that differs from the patient's other moles (the 'ugly duckling').
Check the nails: a new or widening longitudinal pigmented band, or pigment spreading onto the nail fold, is suspicious.

What a positive result means

Positive: a lesion with one or more features, above all recent change, is suspicious and referred for dermoscopy and possible biopsy.
E outweighs the other letters: a mole that changes, grows, bleeds or ulcerates is suspicious even if small.
Nodular melanoma often fails the ABCD: it is a raised, firm, fast-growing lesion, sometimes without pigment.
Acral lentiginous melanoma (palms, soles, nails) is proportionally more common in people with dark skin and is often found late because nobody looks.
A negative ABCDE does not exclude melanoma: there are small, symmetric or non-pigmented (amelanotic) melanomas.

Usefulness and limits

It is a sensitive but not very specific screening rule: many benign atypical naevi meet some letter.
Dermoscopy in trained hands is more accurate than naked-eye inspection.
Diagnosis is confirmed only by biopsy and histopathology.

Test yourself

Think of the answer, then tap the question to see it.

What does each letter of the melanoma ABCDE stand for?

Asymmetry, irregular Border, varied Colour, Diameter over 6 mm and Evolution (change in size, shape, colour or symptoms).

Which ABCDE criterion is considered the most valuable?

E: change over time. A mole that grows or changes is suspicious even if under 6 mm.

Which type of melanoma often fails the ABCD criteria?

Nodular melanoma (and amelanotic melanoma): a raised, firm, fast-growing lesion, sometimes without pigment.

Where does acral lentiginous melanoma appear and why examine those sites?

On palms, soles and nails; it is proportionally more common in dark skin and is diagnosed late because those sites are not checked.

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See it in 3D

The structures of Durgical's 3D anatomy where it is found.

Skin

← All of the clinical exam

Educational content on the clinical exam; it is learned and practised under supervision. It does not replace assessment by a health professional and is not for self-diagnosis.

Sources: What Does Melanoma Look Like? - NCI (National Cancer Institute, 2026); Description of Skin Lesions - Dermatology - Merck Manual Professional Edition (Merck Manuals, 2026); Nail abnormalities: MedlinePlus Medical Encyclopedia (MedlinePlus, U.S. National Library of Medicine, 2026).

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Representative model, for educational purposes only.