Mnemonic

Describing a Skin Lesion

A memory aid for the vocabulary and structure of a dermatological description.

Expansion

Site, distribution, morphology, colour, border, surface and secondary change

Expansion

Primary lesions

Term Definition
Macule Flat, under 1 cm, colour change only
Patch Flat, over 1 cm
Papule Raised, under 1 cm
Nodule Raised, over 1 cm, deeper
Plaque Raised, flat topped, over 1 cm
Vesicle Fluid filled, under 5 mm
Bulla Fluid filled, over 5 mm
Pustule Pus filled
Weal Transient raised oedematous swelling

Secondary change: scale, crust, excoriation, lichenification, fissure, erosion (epidermis only), ulcer (through the dermis), scar, atrophy.

What to describe

  • Site and distribution: symmetrical, extensor or flexor, photodistributed, dermatomal, acral, follicular
  • Number and arrangement: solitary, grouped, linear, annular, target
  • Size and shape
  • Colour, and whether it blanches; a non-blanching purpuric rash is the one that must never be missed
  • Border: well or poorly defined
  • Surface: smooth, scaly, crusted, warty
  • Palpation: temperature, tenderness, consistency, depth
  • Nails, scalp, mucous membranes and the whole skin surface

ABCDE for a pigmented lesion suspicious of melanoma: Asymmetry, Border irregularity, Colour variation, Diameter over 6 mm, Evolution or elevation. Change is the single most important feature.

Fitzpatrick skin type affects appearance; erythema may be difficult to see and presents as violaceous or grey in darker skin, and this is a common source of delayed diagnosis.