Purpura fulminans and venous thrombosis are rare complications of chickenpox. We report the case of a 6 year old with no history individuals who experienced cerebral thrombophlebitis, 3 weeks after varicella. MRI, performed at admission, has objectified longitudinal sinus thrombosis and a frontal parenchymal hematoma law. Meanwhile, a recent varicella seroconversion was demonstrated. The assessment of thrombophilia, meanwhile, has objectified a significant decrease in free protein S and activity, without associated DIC. Origin acquired this deficit was confirmed by the detection of antibodies (IgG and IgM) against the total protein S by ELISA. After evaluation of the benefit/risk only anticoagulation was initiated. The clinical and biological evolution was favorable, with rapid normalization of the S protein and decrease of anti-protein S. Many studies report the presence of anti-protein S in young children at the waning of chickenpox, without their exact frequency is determined. The decrease in protein S they cause leads to a transient hypercoagulable state may result in different clinical pictures. Cases of
purpura fulminans seem more frequent when venous thrombosis isolated post chickenpox, sometimes atypical, appear rare.