From Psoriasis to PsA: The Skin–Joint Axis
Up to 30% of people with psoriasis develop psoriatic arthritis, and nobody can yet say which ones. This review argues the plaque is not just an inflamed patch of skin but a source of immune cells that reach the joint: T cell clones and myeloid precursors shared between skin and synovium. But arrival alone does not cause arthritis. What decides it is the stromal niche, in particular synovial fibroblasts, which act as gatekeepers.