Neonatal purpura fulminans is a rare but life-threatening disorder that presents in a neonate with rapidly progressive intravascular thrombosis and hemorrhagic infarction of the skin. Widespread thrombosis can also cause life-threatening multiorgan failure. This disorder has a mortality rate of over 50% and is associated with severe morbidity in survivors.

Neonatal purpura fulminans is caused by a congenital or acquired absence of protein C and/or protein S that results in a coagulopathy. Rare cases have been associated with antithrombin III deficiency.

Congenital protein C deficiency is caused by a mutation in the PROC gene. Homozygous deficiency is extremely rare and is fatal if not treated. Patients with heterozygous PC deficiency tend to be asymptomatic. However, they are at increased risk of developing purpura fulminans in the setting of increased protein C consumption, such as an infection.

Infectious or idiopathic purpura fulminans can occur in association with or after neonatal infections. Group B streptococcal and gram-negative infections are associated with acquired protein C deficiency in neonates, whereas Neisseria meningitidis and varicella are more common in the adolescent and adult populations. Rare cases of idiopathic purpura fulminans have been reported in infants. See purpura fulminans for further discussion.