Laboratory investigations
The cardinal features of purpura investigations are the same as those of disseminated intravascular coagulation: prolonged plasma clotting times, thrombocytopenia, reduced plasma fibrinogen concentration, increased plasma fibrin-degradation products and occasionally microangiopathic haemolysis. Prevention
For people who have severe congenital protein C deficiency, protein C replacement therapies are available, which is indicated and approved for use in the United States and Europe for the prevention of purpura fulminans. Protein C replacement is often in combination with anticoagulation therapy of injectable low molecular weight heparin or oral warfarin. Before initiating warfarin therapy, a few days of therapeutic heparin may be administered to prevent warfarin necrosis and other progressive or recurrent thrombotic complications. Complications of prevention
The amount of fresh frozen plasma required to reverse disseminated intravascular coagulation associated with purpura fulminans may lead to complications of fluid overload and death, especially in neonates, such as transfusion-related acute lung injury. Exposure to multiple plasma donors over time increases the cumulative risk for transfusion-associated viral infection and allergic reaction to donor proteins found in fresh frozen plasma.Allergic reactions and alloantibody formation are also potential complications, as with any protein replacement therapy.Concomitant warfarin therapy in subjects with congenital protein C deficiency is associated with an increased risk of warfarin skin necrosis. Treatment
Early stage sepsis-associated purpura fulminans may be reversible with quick therapeutic intervention. Treatment is mainly removing the underlying cause and degree of clotting abnormalities and with supportive treatment (antibiotics, volume expansion, tissue oxygenation, etc.).
In later stage lesions, there is irreversible endothelial ischaemic injury with extravasation of blood cells into the dermis and gangrenous necrosis, sometimes with secondary infection.The depletion of anticoagulant and anti-inflammatory proteins, in particular, protein C and its co-factor, protein S, may also promote thrombus formation, inhibit fibrinolysis and lead to further activation of the inflammatory pathways. Diagnosis
Early purpura fulminans lesions look similar to traumatic skin bleeds or purpuric rashes, such as immune thrombocytopenic purpura or thrombotic thrombocytopenic purpura; however, purpura fulminans will rapidly progress to necrosis whereas other purpuric rashes do not. In most cases, differential diagnoses may be distinguished from purpura fulminans by other clinical and laboratory findings.The initial appearance of purpura fulminans lesions is of well-demarcated erythaamatous lesions which progress rapidly to develop irregular central areas of blue-black haemorrhagic necrosis. Advancing areas of necrosis are often surrounded by a thin border of erythaema that fades into adjacent unaffected skin. Haemorrhage into the necrotic skin causes purpura fulminans lesions to become painful, dark and raised, sometimes with vesicle or blister (bulla) formation.The distribution of purpura fulminans lesions may be different according to the underlying pathogenesis. Purpura fulminans in severe sepsis typically develops in the distal extremities and progresses proximally or appears as a generalised or diffuse rash affecting the whole body surface. In cases of severe inheritable protein C deficiency, purpura fulminans with disseminated intravascular coagulation manifests within a few hours or days after birth.