Novel management of post varicella purpura fulminans owing to severe acquired protein S deficiency

Acquired protein S deficiency is a rare complication of varicella zoster infection often resulting in purpura fulminans, which is a potentially life-threatening syndrome of intravascular thrombosis and haemorrhagic infarction of the skin. Patients are presumed to develop crossreacting autoantibodies to the virus and protein S. There is no consensus on how best to manage these patients but previous recommendations focus on plasmapheresis and plasma exchange. We report the case of a 3-year-old girl with post varicella purpura fulminans owing to protein S deficiency, who was diagnosed promptly and made a full recovery following immediate treatment with anticoagulation and plasma support. This suggests that if anticoagulation is used, plasma exchange is not always necessary. As recovery occurred without plasmapheresis, we were able to track protein S levels. The timing of protein S recovery was consistent with the waning titre of an acquired immunoglobulin G autoantibody.