Diagnosis: Protein C deficiency
• Severe protein C deficiency (homozygous protein C deficiency) can present as life-threatening purpura fulminans and disseminated intravascular coagulation (DIC).
• Purpura fulminans is characterized by ecchymotic skin lesions that spontaneously become necrotic. Purpura fulminans is often associated with DIC.
• Protein C is a vitamin K–dependent natural anticoagulant. Activated protein C, with its cofactor protein S, inactivates factors VIIIa and Va.
• Heterozygous hereditary protein C deficiency is seen in 3% of patients with their first venous thromboembolism (VTE) and in only 0.14% to 0.5% of the general population.
• Protein C deficiency increases the risk for VTE by seven-fold.