ABCD Rule for Melanoma Detection: Asymmetry, Border, Color, Diameter

The ABCD mnemonic helps identify suspicious pigmented lesions:

• A – Asymmetry: One half ≠ other half in shape/structure.
• B – Border: Irregular, scalloped, notched, blurred—not smooth.
• C – Color: Variegated: shades of brown/black, ± red, white, blue.
• D – Diameter: >6 mm (pencil eraser), though melanomas can be smaller.

Extended: EFG

• E – Evolution: Change in size, shape, color, elevation, symptoms (itch, bleed).
• F – Firmness: Harder than surrounding skin.
• G – Growth: Rapid enlargement.

Any changing or suspicious lesion warrants dermatology evaluation and possible biopsy. Early melanoma is highly curable.