Axial Psoriatic Arthritis.

PURPOSE OF REVIEW: To review current understanding of the prevalence, clinical features, outcome measures and recent therapeutic trials in axial psoriatic arthritis (axPsA).

RECENT FINDINGS: The prevalence of axPsA is estimated at 40-50%. However, the definition of axPsA remains unclear, therefore these estimates may be inaccurate. Ax PsA appears to be distinct from ankylosing spondylitis in demographic, clinical, genetic and therapeutic features. Because of the lack of widely accepted definition of axPsA it has been difficult to design therapeutic trials for this domain of PsA. Several studies have demonstrated the uniquness of axPsA. Few recent trials suggest that therapies that work for peripheral arthritis also work for axPsA.