Acute infectious purpura fulminans: pathogenesis and medical management.

Purpura fulminans (PF) is a potentially disabling and life-threatening disorder characterized by acute onset of progressive cutaneous hemorrhage and necrosis, and disseminated intravascular necrosis. Acute infectious PF occurs most commonly in the setting of meningococcemia due to elaboration of endotoxin. Presence of purpura, particularly when generalized, is an important predictor of a poor outcome following meningococcal infection. Histopathologic hallmarks of acute infectious PF are dermal vascular thrombosis and secondary hemorrhagic necrosis, findings which are identical to those of the Shwartzman reaction. Acute infectious PF and the Shwartzman reaction have a common pathogenesis, involving a disturbance in the balance of anticoagulant and procoagulant activities of endothelial cells. This disturbance, which is triggered by endotoxin, appears to be mediated by cytokines, particularly interleukin-12, interferon-gamma, tumor necrosis factor-alpha, and interleukin-1, leading to the consumption of proteins C and S and antithrombin III. State-of-the-art therapeutic interventions based on recent advances in our understanding of the pathogenesis of acute infectious PF are discussed.