Morphological description of skin lesions

From Dog
Lesion Description Pattern Association
Macule A circumscribed, flat discoloration of the skin up to 1 cm in diameter Maculopapular; Pigmented
Patch Macules greater than 1 cm Maculopapular; Pigmented
Papule A circumscribed, elevated, superficial, solid lesion up to 1 cm in diameter Maculopapular
Plaque A circumscribed, elevated, superficial solid lesion > 1 cm (Papule enlarged in 2 dimensions Papulonodular- plaque
Wheal An edematous, transitory papule or plaque Papulonodular- plaque; Indurated- turgid
Nodule A solid lesion with depth. A papule that has enlarged in 3 dimensions Papulonodular- nodule
Vesicle A circumscribed elevation of the skin, up to 1 cm in diameter, containing serous fluid Vesiculopustular
Bulla A vesicle > 1 cm in diameter Vesiculopustular
Pustule A circumscribed elevation of skin containing purulent fluid Vesiculopustular
Epidermal collarette A circular peeling rim of scale Vesiculopustular
Petechia A circumscribed deposit of blood or blood pigment up to 1 cm in diameter Pigmented - red
Purpura A circumscribed deposit of blood or blood pigment > 1 cm in diameter Pigmented - red
Scale Shedding dead epidermal cells that may be dry or greasy Exfoliative; Maculopapular
Crust Variously colored collections of skin exudates Erosive-ulcerative
Excoriation Abrasion of the skin, usually superficial and traumatic in origin Maculopapular
Fissure A linear break in the skin, sharply defined with abrupt walls Maculopapular; Papulonodular; Exfoliative
Erosion A skin excavation limited to epidermis and not breaking integrity of dermal-epidermal junction Erosive-ulcerative
Ulcer An irregularly sized and shaped cavitation in the skin extending into the dermis Erosive-ulcerative
Scar A formation of connective tissue replacing tissue lost through injury or disease Indurated
Lichenification A diffuse area of thickening and scaling, with resultant increase in the skin lines and markings Maculopapular; Indurated; Exfoliative
Induration Palpable thickening of the skin Indurated
Sclerosis Hardening of the skin Indurated
Hyperpigmentation Darkening of the skin -