Patients 1, 2, and 3 were eventually managed successfully on anisindione, an alternative to warfarin therapy, for a period. Approximately 2 years after initiating anisindione, patient 1 developed pruritis but no skin lesions. Whether the patient's complaints of pruritis were associated with anisindione was unclear.
In summary, we present 4 patients with late-onset LV suspected to be due to a delayed reaction to long-term warfarin therapy. The skin manifestations in all 4 patients resolved with warfarin withdrawal, and in 2 out of 4 patients, recurrence occurred on rechallenge (patients 1 and 2). With an increasing number of patients being prescribed long-term warfarin therapy, it is important to alert clinicians to this rare and perplexing complication. We also encourage accurate documentation of future cases so that the clinical presentations can be accurately described and pathologic mechanisms elucidated.
At the time of this publication, it is not clear whether anisindione is still available. The unavailability of this agent further adds to the challenge of managing future patients who develop this complication and still require long-term anticoagulation therapy.
Acknowledgments—The authors would like to thank Angela Su, PharmD; Francisco Quismorio, MD; and Earl C. Harrison, MD, for their contributions in preparing this manuscript.