Barrier breakdown: insights into the skin-gut axis in psoriatic arthritis

Psoriatic arthritis (PsA) is a chronic inflammatory disease that primarily affects the skin, joints, and entheses. Growing evidence implicates alterations at the gut and skin barriers in PsA pathogenesis. These sites play a crucial role in tissue homeostasis, and their disruption can contribute to the translocation of immune cells and bacterial products, resulting in systemic inflammation. Crosstalk between barrier sites and joints can promote or exacerbate disease development, with barriers also being a potential target of disease. This review article provides a barrier-centered perspective across gut, skin, and synovium, with a specific focus on new concepts about intertissue communication involving immune and microbial mediators that can propagate inflammation in PsA.