Abstract: Objectives: The term cutaneous vasculitis (CV) includes a wide and heterogeneous group of entities. The American College of Rheumatology (ACR) established a set of criteria to classify vasculitis in 1990. Our aim was to further investigate into the applicability of these criteria for the classification of patients with primary CV.
Methods: We analysed a large and unselected series of patients with CV attended to a university referral centre from January 1976 to December 2011. Patients were classified according to the methodology and criteria proposed by the ACR1990 core data set. Patients were also classified according to the same ACR 1990 database as proposed by Michel et al. in 1992 to differentiate Henoch-Schönlein purpura (HSP) from hypersensitivity vasculitis (HV).
Results: We assessed 766 patients (346 women and 420 men) with a mean age of 34 years. Patients with cutaneous lesions in the setting of conditions different from primary CV were excluded. According to the 1990 ACR criteria, 405 (63.1%) of the 642 patients with primary CV were classified as having HSP and 230 (35.8%) as HV. However, 119 (18.5%) patients fulfilled the ACR 1990 criteria for both entities. In addition, 7 (1.1%) did not meet the ACR 1990 criteria for any of them and, therefore, they were considered as non-classified vasculitis. When patients with primary CV were tested for the Michel et al. criteria, 392 (61.1%) were classified as having HSP and 250 (38.9%) as HV. Frequent discordance between the ACR 1990 and the Michel et al. criteria was observed. It ranged between 18.4 and 21.7% for HSP and 32.2 to 38% for HV.
Conclusions: According to our data, the ACR 1990 criteria are of limited value for the classification of patients with primary CV.