Derm Terminology

Bulla: vesicle greater than 1 cm.
Crust: lesion of dried serous exudate, pus or blood.
Ecchymosis: subepidermal hemorrhage, initially blue-black, then green-brown or yellow. Non-blanching.
Lesion: area of altered tissue
Macule: non-palpable, discolored lesion lessthan 1 cm
Nodule: elevated palpable lesion with indistinct borders. Outside the elevated area, can palpate some of the lesion below the skin.
Papule: elevated palpable lesion with circumscribed borders, less than 1 cm.
Patch: macule greater than 1 cm.
Petechia: pinpoint nonblanching hemorrhagic spot.
Plaque: papule > 1 cm, or coalescence of several papules
Purpura: small hemorrhagic spot, non-blanching, larger than a petechiae, 1-3 mm.
Scale: exfoliation of dead or dying bits of skin; can also result from excess keratin.
Vesicle: elevation of skin filled with serous fluid and less than 1 cm (blister)
Wheal: dermal fluid collection, appears as reddened solid elevation of skin.