 Acquired protein C deficiency is caused by either depletion of available protein C in plasma or decreased protein C synthesis (caused by administration of vitamin K antagonists, severe liver failure or complications of prematurity).Purpura fulminans is a presenting feature of severe acute sepsis, such as Neisseria meningitidis, Streptococcus pneumoniae, Group A and B Streptococci, and less commonly with Haemophilus influenzae, Staphylococcus aureus, or Plasmodium falciparum (malaria) infections, particularly in individuals with asplenia.In some cases, a combination of sepsis and a partial congenital defect in the protein C anticoagulant pathway initiates purpura fulminans.