question: Postvaricella protein S deficiency is a rare and severe disease. We report a case of extensive necrotic skin lesions of acute onset 7 days after varicella in a 4-year-old girl. Protein S antigen and activity were <10%, and antiprotein S antibodies were detected. She was treated with anticoagulation, plasmapheresis and fresh frozen plasma. She survived but required leg amputation.