ABCD Rule of Dermoscopy (Total Dermoscopy Score)

Scores a melanocytic skin lesion on dermoscopy (asymmetry, border, color, structures) to stratify melanoma risk; a triage aid for melanocytic lesions only, not a histologic diagnosis.

Asymmetry (A) — axes showing asymmetry (×1.3)

Border (B) — segments (of 8) with an abrupt cutoff (×0.1)

Color (C) — check each color present (count ×0.5):

White

Red

Light brown

Dark brown

Blue-gray (slate)

Black

Differential structures (D) — check each present (count ×0.5):

Pigment network

Structureless (homogeneous) area

Branched streaks (radial streaming / pseudopods)

Dots

Globules