Can traumatic injury trigger psoriatic arthritis? A review of the literature.

Traumatic injury as a trigger for the subsequent development of psoriatic arthritis (PsA) has been implicated by several case reports and case series. However, it is still unclear whether trauma is the inciting event or just an incidental finding. It is thought that the interplay of genetic, immunologic, and environmental factors, such as trauma, may trigger the development of PsA. At least two hypotheses of how trauma may be linked to the development of PsA have surfaced and involve a "deep Koebner effect," the concept of a synovio-entheseal complex and activation of the innate immune system by biomechanical factors. The role of neuropeptides such as substance P and vasoactive intestinal peptide has been highlighted in the synovium after trauma. Better understanding of this phenomenon would shed light into the pathophysiology of Psa and help the development of preventive and therapeutic strategies.