Vascular Disturbances of the Skin in Patients Who Are Critically Ill: Lines, Dots, Patches

When an understanding of pathogenesis exists, skin lesions that have the appearance of blood in the skin can provide insight into the mechanisms leading to a systemic process that results in cutaneous manifestations. Of the vascular disturbances of the skin that occur in patients who are critically ill, some result from a nonhemorrhagic process, whereas others represent bleeding into the skin. The lesions of livedo, petechiae, purpura, and ecchymoses can be approached from such a perspective. In their most characteristic forms, they develop because of problems with platelets, blood vessels, and hypocoagulability. The tactile component of palpability in their clinical evaluation can denote that inflammation is part of the process. The goal of this review is to provide a conceptual approach not only to the diagnosis of vascular disturbances of the skin, but also to the pathophysiologic processes occurring that might offer clues to the underlying disease process.