spondyloarthritis

Spondyloarthritis (SpA) is a family of inflammatory rheumatic diseases that share clinical features such as inflammatory back pain, enthesitis (inflammation at tendon and ligament insertion sites), and a tendency toward extra-articular involvement. The conditions encompass axial spondyloarthritis, which primarily affects the spine and sacroiliac joints, and peripheral spondyloarthritis, in which peripheral joints and entheseal sites are involved.

Axial spondyloarthritis (axSpA) includes radiographic disease, commonly known as ankylosing spondylitis, and non-radiographic axSpA, where imaging may not show changes on X-ray but symptoms and MRI findings support the diagnosis. Peripheral SpA includes psoriatic arthritis, reactive arthritis (formerly Reiter syndrome), arthritis associated with inflammatory bowel disease, and undifferentiated SpA.

Common features include inflammatory back pain with gradual onset, morning stiffness that improves with exercise, and progressive axial involvement. Enthesitis, dactylitis, and peripheral arthritis may occur, often with extra-articular manifestations such as uveitis, psoriasis, or inflammatory bowel disease. Genetic predisposition, particularly HLA-B27 positivity, and family history increase risk. The condition typically begins in young adulthood, with a male predominance in axial disease.

Diagnosis combines clinical assessment with imaging (X-ray or MRI of the spine and sacroiliac joints) and serologic tests, including HLA-B27 and inflammatory markers. Classification criteria, such as the ASAS criteria, aid identification of axSpA; recognition of peripheral features supports the broader SpA diagnosis.

Treatment centers on regular physical therapy and NSAIDs as first-line therapy. When needed, biologic therapies targeting TNF or IL-17, along with conventional DMARDs for peripheral arthritis, are used. Management also addresses extra-articular disease and lifestyle factors such as smoking cessation.