New biological treatments for psoriatic arthritis.

P soriatic arthritis (PsA) is a chronic inflammatory arthropathy of unknown etiology [1] that affects as many as onethird of patients with psoriasis. Together with entero-associated arthritis (EA), reactive arthritis (ReA), ankylosing spondylitis (AS) and undifferentiated spondyloarthritis (uSpA), it is a member of the spondyloarthritis (SpA) family of rheumatic diseases [2] whose overlapping features include arthritis of the axial skeleton, inflammatory back pain, uveitis, dermatological and gastroenterological involvement, and a genetic association with human leukocyte antigen (HLA)-B27. It affects men and women equally (although the presence of axial disease is three times more frequent in men), and appears mainly between the ages of 30 and 50 years. Its various manifestations include mono-oligoarthritis, an erosive and destructive polyarthritis that cannot be distinguished from rheumatoid arthritis, and spondyloarthropathy with axial involvement or enthesitis, but it is also complicated by comorbidities such as cardiovascular and metabolic diseases.