[Psoriatic arthritis, a difficult diagnosis due to clinical polymorphism].

: Psoriatic arthritis, a difficult diagnosis due to clinical polymorphism. Psoriatic arthritis (PsA) is a chronic inflammatory spondyloarthritis that occurs in combination with psoriasis. The prevalence is similar to rheumatoid arthritis. The diagnosis is difficult because the disease is heterogeneous, involving skin, nails and different musculoskeletal structures. There are no pathognomonic serological marker. Psoriasis usually appears 5-10 years before PsA, although some patients presents with PsA without psoriasis. TNF inhibitors (tumor necrosis factor: biological agents) have revolutionized therapy for PsA; there are effective against all disease characteristics, however not all patients achieve clinically meaningful responses and some may respond initially but lose treatment responses over time. With a better understanding of immunological mechanisms underlying psoriasis and PsA, new therapies have been developed to target specific components of the inflammatory pathway. IL17-17A and IL23 inhibitors agents (Th 17-IL17A pathway) has been shown to be efficacious. PsA is associated with a premature mortality, increased cardio vascular morbidity, obesity, metabolic syndrome. Collaboration between rheumatologist, dermatologist and general practitioner for the evaluation of morbidities, is be necessary in managing patients with PsA.