Warfarin-induced Skin Necrosis

Your doctor prescribing you Warfarin(rat poison) will have told you all the side effects to looks for. Purple toe, etc.
http://onlinelibrary.wiley.com/doi/10.1002/9781118618189.ch36/summary
Patients who are deficient in protein C and S are at most risk for this complication.
Because routine screening for protein C and S deficiency is not part of the standard of care
for warfarin therapy, detection of this subset of patients is often not possible