Warfarin-Induced Skin Necrosis (WISN)
Some pearls about a rare, but serious side effect of Warfarin...
- WISN Occurs in 0.01-0.1% of patients taking Warfarin
- More common in middle-age, perimenopausal women being treated for DVT/PE
- Symptoms usually begin on days 3-6 of Warfarin treatment
- Underlying pathophysiology is complex but involves thrombosis of superficial dermal capillaries
- Postulated to be associated with deficiencies of protein C, protein S, and antithrombin III
- Rash is most common on the breats, with thighs/buttocks being second most common site (see picture)
- Diagnosis usually made clinically based on appearance of rash
- Treatment is aimed at restoring Vitamin K dependent clotting factors by administering Vit K and FFP
- For patients with the need for anticoagulation (DVT/PE, etc.) Heparin therapy is usually started
55 yo female presented to the ED on the day of hospital discharge for evaluation of this rash.
The rash began 4 days after starting Warfarin. Was being treated for a DVT.