Urticarial Vasculitis Associated With Levothyroxine.

Urticarial vasculitis (UV) is a protean disorder that can be triggered by a myriad of causes although it is often idiopathic. Treatment is often successful with corticosteroids and/or immunosuppressive drugs. However, when a cause is found, specific treatment of the underlying problem or removal of an offending agent will resolve the symptoms. This report describes a patient with UV triggered by thyroid replacement, necessitated by Hashimoto's thyroiditis, which can itself cause UV. In this unusual presentation, rather than thyroiditis, thyroid replacement was the trigger for the vasculitis.