S-51 Division of Rheumatology 1 , Internal Medicine 2 , Pedriatrics 3 , Pathology 4 , and Dermatology 5 . Hospital Universitario Marqués de Valdecilla, IDIVAL, University of Cantabria. Santander, Spain. Francisco Ortiz-Sanjuán, MD* Ricardo Blanco, MD, PhD* Javier Loricera, MD José Luis Hernández MD, PhD** Trinitario Pina MD Vanesa Calvo-Río, MD Lino Álvarez, MD M Carmen González-Vela, MD, PhD Javier Rueda-Gotor, MD Marcos A. González-López MD, PhD Miguel A. González-Gay, MD, PhD** *Drs. Ortiz-Sanjuán and Blanco shared frst authorship. **Drs. González-Gay and Hernández shared senior authorship. Please address correspondence to: Miguel A. González-Gay or Ricardo Blanco, Rheumatology Division, Hospital Universitario Marqués de Valdecilla, Avda. Valdecilla s/n., 39008, Santander. Spain. E-mail: miguelaggay@hotmail.com rblanco@humv.es Received on February 24, 2014; accepted in revised form on March 27, 2014. Clin Exp Rheumatol 2014; 32 (Suppl. 82): S51-S54. © Copyright CliniCal and ExpErimEntal rhEumatology 2014. Funding: this study was supported by a grant from “Fondo de Investigaciones Sanitarias” PI12/00193 (Spain), and was also partially supported by RETICS Programs, RD08/0075 (RIER) and RD12/0009/0013 from ‘‘Instituto de Salud Carlos III’’ (ISCIII) (Spain). Competing interests: none declared. ABSTRACT Objective. The term cutaneous vascu- litis (CV) includes a wide and heteroge- neous group of entities. The American College of Rheumatology (ACR) estab- lished a set of criteria to classify vas- culitis in 1990. Our aim was to further investigate into the applicability of these criteria for the classifcation 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 classifed according to the methodology and criteria proposed by the ACR1990 core data set. Patients were also classifed according to the same ACR 1990 database as proposed by Michel et al. in 1992 to differenti- ate 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 dif- ferent from primary CV were excluded. According to the 1990 ACR criteria, 405 (63.1%) of the 642 patients with primary CV were classifed as having HSP and 230 (35.8%) as HV. However, 119 (18.5%) patients fulflled the ACR 1990 criteria for both entities. In ad- dition, 7 (1.1%) did not meet the ACR 1990 criteria for any of them and, therefore, they were considered as non- classifed vasculitis. When patients with primary CV were tested for the Michel et al. criteria, 392 (61.1%) were classi- fed 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. Conclusion. According to our data, the ACR 1990 criteria are of limited value for the classifcation of patients with primary CV. Vasculitis is a general term for a group of related disorders characterised by blood vessel infammation leading to tissue or organ injury. Tissue biopsy is the cornerstone of the diagnosis of vas- culitis (1). However, in the daily clini- cal practice it is not exempt of potential limitations as sometimes it provides an incomplete or non-specifc pathologic result. In addition, biopsy is not always feasible and it is not routinely performed in typical cases of cutaneous vasculitis (CV), in particular in children. Classifcation of vasculitis has been a challenging problem for decades. Diagnosis often relies on a combina- tion of clinical, laboratory and histo- pathologic fndings. For this reason, in 1990, the American College of Rheumatology (ACR) proposed a se- ries of classifcation criteria based on data comparing clinical features of patients with seven types of primary vasculitis: Giant Cell Arteritis (GCA), Takayasu Arteritis (TA), Wegener’s Granulomatosis (WG), Churg-Strauss Syndrome (CSS), Polyarteritis Nodosa (PAN), Hypersensitivity Vasculitis (HV) and Henoch-Schönlein Purpura (HSP) (2). The term “cutaneous vasculitis” (CV) refers to a wide and heterogeneous group of entities linked by the presence of necrotising infammatory lesions in the cutaneous blood vessels (3). The clinical spectrum and epidemiology of CV may range from an isolated cutane- ous involvement to a life-threatening syndrome (3, 4), including conditions that following defnitions proposed Reappraisal of the 1990 American College of Rheumatology criteria for the classifcation of cutaneous vasculitis: an analysis based on 766 patients F. Ortiz-Sanjuán 1 , R. Blanco 1 , J. Loricera 1 , J.L. Hernández 2 , T. Pina 1 , V. Calvo-Río 1 , L. Álvarez 3 , M.C. González-Vela 4 , J. Rueda-Gotor 1 , M.A. González-López 5 , M.A. González-Gay 1