Purpuric Cutaneous Lesions: A Pathophysiological Framework for Diagnosis

Abstract Purpuric skin lesions are caused by the extravasation of red blood cells from the cutaneous blood vessels. There are multiple mechanisms that cause this phenomenon, such as coagulation disorders, weakness and inflammation of the vessel wall, and occlusion of the vessel lumen. The clinical characteristics of purpuric skin lesions (size, colour, and distribution) can point towards the underlying specific pathophysiological mechanism. Coupled with the patient interview, exploration, and laboratory tests, it is possible to determine the diagnosis and provide the patient the proper medical treatment. Purpuric skin lesions can be potentially fatal because of their relationship with systemic disorders leading to the potential organ failure; herein resides the importance of recognizing and treating the lesions rapidly. In this article we suggest a practical approach to purpuric skin lesions according to their pathophysiological mechanisms and fatal risks.