Protein C and protein S levels in two patients with acquired purpura fulminans.

Purpura fulminans (PF) is a cutaneous manifestation of a dramatic and deadly syndrome of systemic disseminated intravascular coagulation (DIC). It is characterized by microvascular thrombosis in the dermis followed by perivascular haemorrhage. Since two other related syndromes involve the protein C (PC) system, we undertook a serial study to investigate the levels of PC and protein S (PS) in two patients with acquired PF. Laboratory findings were consistent with DIC, and both patients were treated with blood replacement and heparin therapy. The levels of PC activity were very low during the initial 24-36 h after onset and gradually increased until returning to normal levels. The total and 'free' PS were also abnormal during the initial onset of PF. The total and free PS increased to normal after 4-6 d. Although the pathogenesis is not fully understood, the infection and sepsis appears to consume PC and PS selectively during the PF and DIC phase. Acquired PF appears to selectively involve the PC system in a similar fashion to two other syndromes of PF-like lesions.