RESUMO
BACKGROUND: Congenital protein C deficiency is a rare hereditary thrombophilia, neonatal purpura fulminans is the most serious form of this deficit. The purpose of this observation is two-fold. The first is the need to make an early diagnosis in order to improve the prognosis. The second, is to discuss the need. In case of extensive purpura fulminans in the neonatal period, the search for a deficiency in anticoagulant factor, in particular the dosage of protein C, in the newborn and in both parents. METHODS: The diagnosis is biological and is based on the quantitative determination of functionally active protein C. We use the Berichrom® Protein C assay on an automated coagulation analyzer from Siemens Healthcare Diagnostics, which allows the chromogenic determination of Protein C activity. RESULTS: We report an observation of cutaneous necrosis in a newborn having developed a purpura fulminans extensive secondary to a total congenital protein C deficiency. In front of this clinical picture, thrombophilia assessment is requested, revealing an isolated deficit in protein C < 1%. CONCLUSIONS: In the case of extensive purpura fulminans in the neonatal period, the search for a deficiency in anticoagulant factor, in particular the dosage of protein C, is essential in the newborn and in both parents.