Axial Disease in Psoriatic Arthritis: how can we Define it, and does it have an Impact on Treatment?

The Spondyloarthritis (SpA) represents a group of rheumatic inflammatory entities that share clinical, laboratory and imaging features, including Psoriatic Arthritis (PsA). Axial involvement may occur in up to 50% of patients with PsA (axPsA), causing inflammatory back pain, stiffness and changes on imaging. Whether axial SpA (axSpA) with psoriasis represents a distinct entity than axPsA is a matter of debate, since similarities and differences have been reported in terms of clinical expression and imaging. Patients with radiographically axPsA show lower prevalence of inflammatory b ack pain, lumbar and buttock pain in comparison with axSpA. In addition, imaging features differ between axPsA and axSpA, with less sacroiliitis in axPsA and more asymmetrical, chunky syndesmophytes which are predominant at the cervical spine location. Data on treatment efficacy and management recommendations are extrapolated from studies on axSpA, and only one published randomized clinical trial is dedicated specifically to axPsA to date.