RT Journal Article SR Electronic T1 Editorial: Late-Onset Spondyloarthritis: Subset That Should Not Be Forgotten JF The Journal of Rheumatology JO J Rheumatol FD The Journal of Rheumatology SP jrheum.120184 DO 10.3899/jrheum.120184 A1 Ignazio Olivieri A1 Salvatore D'Angelo A1 Carlo Palazzi A1 Pietro Leccese A1 Angela Padula YR 2012 UL http://www.jrheum.org/content/early/2012/05/14/jrheum.120184.abstract AB The spondyloarthritis (SpA) complex embraces ankylosing spondylitis (AS), reactive arthritis (ReA), psoriatic arthritis (PsA), arthritis related to inflammatory bowel disease (IBD), and forms that do not fulfil established criteria, which are labelled as undifferentiated SpA (uSpA). In the early 1990s, 2 sets of classification criteria were suggested to encompass the clinical spectrum of SpA: the Amor criteria and the European Spondylarthropathy Study Group (ESSG) criteria.