Dermatologic nomenclature

Primary lesions

Small lesions (<0.5cm)

1. Macule – flat, cirumscribed, colored, non palpable
2. Papule – raised, solid and palpable
3. Vesicle – raised, palpable, clear fluid-filled
4. Pustule – raised, palpable, pus filled (leukocytes or keratin)

Large lesions (>0.5cm)

1. Patch – large macule (flat non-palpable colored area)
2. Plaque – superficially raised, circumscribed solid area
3. Nodule – distinct large papule
4. Bulla - large vesicle (blisters if epidermal layer completely sloughed off)
5. Wheal – firm and edematous plaque (edema of the dermis)

Secondary lesions

Section One

1. Scales – dead epidermal cells (dry white dandruff)
2. Cursts – dead epidermal cells + serum (oily secretions)/pus
3. Erosion –focal effacement of epidermis
4. Ulcer – focal effacement of epidermis +dermis
5. Fissure – linear crack into epidermis +dermis
6. Atrophy – thinning of epidermis +dermis
7. Scar – healed skin with connective and epithelialized granulation tissue
8. Lichenification – thickened epidermis
9. Petechia – non-blanching, micro- hemorrhages (3mm) into the dermis
10. Purpura - non-blanching, small hemorrhage (0.5-1cm) into dermis
11. Ecchymoses – large area of hemorrhage into dermis (a.k.a bruising)

Source

1. Emedicine
2. Wikipedia