Preventing psoriatic arthritis: focusing on patients with psoriasis at increased risk of transition.

Psoriasis is one of the most common chronic inflammatory skin diseases, affecting 3% of the world's population, and approximately one-third of patients with psoriasis will eventually transition to having psoriatic arthritis (PsA). The evolution from cutaneous to synovio-entheseal inflammation in these patients presents an opportunity to investigate the critical events linked to arthritis development. The events responsible for progression to PsA are currently unclear. Genetic and clinical-demographic risk factors (most notably familial aggregation and psoriasis sub-phenotypes) provide relevant insights into the variables that promote transition. The specific underlying molecular and cellular mechanisms, however, remain poorly defined. Intriguingly, although targeting the IL-23-IL-17 axis substantially improves psoriasis outcomes, this strategy is not more effective than TNF inhibitors in improving musculoskeletal symptoms in PsA. Major unmet needs in the field of PsA include defining those patients with psoriasis at increased risk of developing arthritis, improving our understanding of the natural history of disease and characterizing the immune, environmental and molecular subclinical events preceding PsA onset. Improving our knowledge of this transition is essential for designing clinical trials with treatments that can delay, attenuate or even prevent the development of PsA in patients with psoriasis.