Overview of the 2012 revised International Chapel Hill Consensus Conference nomenclature of vasculitides.

The nomenclature and classification of vasculitis has been difficult and controversial for many decades. This is problematic both for research on vasculitis as well as clinical care of patients with vasculitis. The first (1994) International Chapel Hill Consensus Conference on the Nomenclature of Systemic Vasculitides (CHCC) proposed names and definitions for the most common forms of vasculitis. Since then, there have been substantial advances in our understanding of vasculitis and changes in medical terminology. In addition, CHCC 1994 did not propose a nomenclature for some relatively common forms of vasculitis, such as vasculitis secondary to other diseases. To address these issues, a second International Chapel Hill Consensus Conference was held in 2012. The goals were to change names and definitions as appropriate, and add important categories of vasculitis not included in CHCC 1994. This overview summarizes the 2012 CHCC and points out the changes compared to the 1994 CHCC. Notable changes include the introduction of new terms such as granulomatosis with polyangiitis, eosinophilic granulomatosis with polyangiitis and immunoglobulin A vasculitis and the inclusion of categories for variable vessel vasculitis and secondary forms of vasculitis.