spondyloarthritisankylosing

Spondyloarthritis (SpA) is a family of inflammatory rheumatic diseases that share features such as inflammatory back pain, entheseal inflammation, and a tendency toward extra-articular involvement. The group includes axial spondyloarthritis (axSpA) with or without radiographic sacroiliitis, peripheral SpA, and SpA associated with inflammatory bowel disease, psoriasis, or reactive arthritis. A common genetic association with HLA-B27 is found in many patients, although its presence is not required for diagnosis.

Ankylosing spondylitis (AS) is the prototypical axial SpA. It typically begins in adolescence or early adulthood with chronic inflammatory back pain that improves with exercise but not with rest and is accompanied by morning stiffness. Sacroiliitis and progressive spinal inflammation may lead to reduced spinal mobility and, in advanced cases, spinal fusion. Peripheral joint involvement and enthesitis can occur.

In axSpA, a distinction is made between radiographic axial SpA (ankylosing spondylitis) and non-radiographic axial SpA, with MRI allowing earlier detection before radiographic changes. Other SpA conditions include psoriatic arthritis with axial involvement, reactive arthritis, and Crohn’s disease- or ulcerative colitis-associated arthritis.

Diagnosis combines clinical features, inflammatory markers, HLA-B27 testing, and imaging findings. Treatment starts with NSAIDs and structured physical therapy; many patients require escalation to biologic therapies such as TNF inhibitors or IL-17 inhibitors. Conventional DMARDs have limited effect on axial disease but may help peripheral arthritis; sulfasalazine is sometimes used in peripheral SpA. Lifestyle measures, smoking cessation, and vaccination are important.

The prognosis varies with disease activity and treatment. Early recognition and effective therapy improve function and quality of life and may slow radiographic progression. AS is more common in men, often beginning before 45 years of age; overall SpA affects roughly 0.5–1% of the population, with axial disease being a major component.