Hemorrhagic necrosis that was first demonstrated in rabbits with a two-step reaction, an initial local (intradermal) or general (intravenous) injection of a priming endotoxin (ENDOTOXINS) followed by a second intravenous endotoxin injection (provoking agent) 24 h later. The acute inflammation damages the small blood vessels. The following intravascular coagulation leads to capillary and venous THROMBOSIS and NECROSIS. Shwartzman phenomenon can also occur in other species with a single injection of a provoking agent, and during infections or pregnancy. Its susceptibility depends on the status of IMMUNE SYSTEM, coagulation, FIBRINOLYSIS, and blood flow.