<prompt> Warfarin skin necrosis is caused by-Protein CProtein S deficiencyAPLAVitamin K deficiencyFibrinogen deficiency  <response>: Ans. a Protein CProtein S deficiencyRef: Wintrobes 12thpg 1490Warfarin skin necrosisDue to warfarin-induced rapid reduction in protein C levels in patients with a pre-existing inherited protein C deficiency that results in a hypercoagulable state and thrombosis.Not all heterozygous protein C-deficient patients receiving warfarin experience this complication, and not all patients with this complication have protein C deficiency. 