Snapshot A newborn baby girl with no birth complications develops red purpuric lesions on the buttocks, elbows, and heels. She is lethargic and does not respond to soothing ointments. A pediatric dermatologist is consulted. By the time, the specialist sees the newborn, black eschars have formed on the pressure points. She is diagnosed with purpura fulminans and dies shortly after. Introduction Hypercoagulable state/thrombophilia caused by deficiency in protein C or S Mnemonics skin or subcutaneous necrosis after administration of warfarin login to view 1 more bullet protein C deficiency is more common than protein S deficiency “protein C Cancels Coagulation” ETIOLOGY Pathogenesis review of anticoagulation pathway login to view 3 more bullets deficiency of either protein C or S → active factors V and VIII login to view 1 more bullet Genetics inherited login to view 2 more bullets acquired login to view 3 more bullets Presentation Symptoms of thrombosis after warfarin initiation login to view 1 more bullet DVT or PE at a young age increased risk of DIC In severe cases purpura fulminans in newborns login to view 2 more bullets STUDIES Protein C or S functional assay (preferred) ↓ protein C or S activity levels Plasma protein C or S antigen levels ↓ protein C or S antigen levels Genetic testing not routinely done Differential Diagnosis Factor V Leiden mutation Antithrombin deficiency Antiphospholipid syndrome HIT Treatment Prevention avoid warfarin avoid conditions that increase risk of thrombosis login to view 1 more bullet For thrombosis protein C concentrate anticoagulate with heparin For warfarin-induced necrosis stop warfarin administer IV vitamin K administer heparin administer protein C concentrate or fresh frozen plasma Complications Miscarriage Thrombosis neonatal purpura fulminans Prognosis Severe disease associated with neonatal mortality Risk of warfarin-induced skin necrosis