petechiae purpura definition
A petechia, plural petechiae, is a small (1â2 mm) red or purple spot on the skin, caused by a minor bleed from broken capillary blood vessels. Petechia refers to one of the three descriptive types of bleeding into the skin differentiated by size, the other two being purpura and ecchymosis. Petechiae are by definition less than 3 mm. The term is almost always used in the plural, since a single lesion is seldom noticed or significant.