medical term for a subcutaneous purpura larger than 1 centimeter or a hematoma, commonly called a bruise. It can be located in the skin or in a mucous membrane.
After local trauma, red blood cells are phagocytosed and degraded by macrophages. The blue-red color is produced by the enzymatic conversion of hemoglobin into bilirubin, which is more blue-green. The bilirubin is then converted into hemosiderin, a golden brown color, which accounts for the color changes of the bruise.[1]
Hematomas can be subdivided by size. By definition, ecchymoses are 1 to 2 cm in size or larger, and are therefore larger than petechia (1–2 mm) or pigmented purpuric dermatosis (>3 mm).[1] Hematomas also have a more diffuse border than other purpura.[2]
Generally speaking, dermatologists prefer to differentiate between purpurae, petechia, and ecchymoses as descriptive technical terms. Other specialties such as internal medicine will frequently call all of these ecchymoses, because the finer distinction is not relevant in the particular case
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