The classification of vasculitis is based on a combination of clinical features and pathology. The conventional classifications of systemic vasculitis are based on the size of the dominantly involved blood vessels and on the presence or absence of other conditions as the cause of vasculitis. There are two main systems of classification in use:


  • The American College of Rheumatology (ACR) classification criteria which were developed in 1990. These were validated against other patients with vasculitis but not against non-vasculitis controls. It should be stressed that they are NOT intended for use as diagnostic criteria and they perform poorly when used for that puropse. The other main criticism is that they do not include ANCA in the criteria, nor is microscopic polyangiitis considered.
  • The Chapel Hill consensus definitions (CHCC) were produced in 1994 and provide clear definitions of the conditions but again were not intended for use as either diagnostic or classification criteria. However, they are widely used for this purpose.

In order to rationalise the use of both systems in epidemiology the EMEA algorithm has been developed by a consensus group to harmonise the use of the ACR criteria and the CHCC definitions.

A working group supported by the European League Against Rheumatism (EULAR) and the American College of Rheumatology (ACR) is currently revising the definitions and classification criteria for vasculitis. Endorsed by the European League against Rheumatism (EULAR), Points to Consider in the Development of Classification and Diagnostic Criteria in Systemic Vasculitis were published in the Annals the Rheumatic Diseases in 2010. The clinical study to develop new Diagnostic and Classification criteria in VASculitis (DCVAS) started in 2010. Further information at