Objective: To examine the value of the American College of Rheumatology (ACR) 1990 criteria for Henoch-Schönlein purpura (HSP) and hypersensitivity vasculitis (HSV) and the Chapel Hill Consensus Conference (CHCC) definition of cutaneous leukocytoclastic angiitis (CLA) in the classification of cutaneous vasculitis and to estimate the annual incidence of biopsy proven cutaneous vasculitis in a well defined population.
Methods: ACR criteria for HSP and HSV and the CHCC definition for CLA and HSP were applied to an unselected cohort of 84 patients with biopsy proven cutaneous vasculitis attending a single district hospital in the United Kingdom between January 1990 and December 1994.
Results: Thirty-seven patients fulfilled ACR criteria for HSV, of whom 27 also fulfilled the ACR criteria for HSP. Thirty-two patients met the CHCC definition for CLA and 7 the CHCC definition for HSP. The overall annual incidence of cutaneous vasculitis was 38.6/million (95% CI 30.6-48.1), and for CLA 15.4/million (95% CI 10.6-21.8).
Conclusion: The ACR 1990 criteria for HSP and HSV overlap; the CHCC definitions for CLA and HSP provide clearer distinction. Cutaneous vasculitis is as common as systemic vasculitis.