The Poison Review

Warfarin-Induced Skin Necrosis. Inayatullah S et al.  South Med J Jan 2010;103:74-75.

Abstract

Warfarin-induced skin necrosis (WISN) is a rare (estimated prevalence 0.01 – 0.1%) but severe condition that all clinicians should be aware of.  It usually occurs within 1-10 days of starting warfarin, and is probably related to a drug-induced relative deficiency of the anticoagulation factor protein C, creating a paradoxical hypercoagulable state. The presence of WISN is often heralded by paresthesias or a sensation of pressure or discomfort.  This is followed by painful, localized hemorrhagic or erythematous lesions.

This short case report reminds us that WISN exists, but is otherwise so confused and lacking in detail that it is not worth tracking down.  The authors say that they identified their patient as at risk for developing WISN, but don’t say why.  Although a protein C deficiency is the major risk factor for WISN, they did not measure levels, nor do a skin biopsy.  It is not at all clear that this case did not represent another entity, such as heparin-induced skin necrosis.

There is a good short discussion of WISN in the University of Cincinnati’s Lab Lines. It is also important to note that although WISN is rare and most clinicians have probably never seen a case, it has made an appearance on House.