Hidradenitis suppurativa associated with spondyloarthritis -- results from a multicenter national prospective study.

Objective: To determine the prevalence and characterize the inflammatory musculoskeletal symptoms of hidradenitis suppurativa (HS), a chronic inflammatory disease of skin appendages.

Methods: Patients with HS referred to 3 dermatology university hospital centers were systematically screened for peripheral arthritis, dactylitis, inflammatory back pain, or enthesitis. After careful clinical examination, patients were further classified according to clinical and imaging criteria for spondyloarthritis (SpA) using the Amor, European Spondyloarthropathy Study Group (ESSG), and ASsessment in ankylosing spondylitis (ASAS).