Urticarial vasculitis (UV) is a small vessel vasculitis and an immune-complex mediated disease like other leukocytoclastic vasculitis. UV seems similar to common urticaria clinically. Major difference between urticarial vasculitis and urticaria is the duration of lesions. Urticarial lesions regress in 24 hours, but UV lesions persist longer than 24 hours. Residual hyperpigmentation, constitutional symptoms like fever, arthralgia, and abdominal pain are other main clinical differences between these disorders. Upon confirmation of diagnosis, patients are divided into two major categories on the basis of serum complement levels: normocomplementemic UV (NUV) and hypocomplementemic UV (HUV). Consensus meeting in 1996 stated that long lasting (at least 24 hour–5 days) indurated wheals, which may be itchy, painful or tender, be associated with purpura and presence of associated extracutaneous findings, and cutaneous vasculitis confirmed by histopathological examination are defined as UV.
Part of the book: Urticaria and Angioedema