spondyloarthritides

Spondyloarthritides (SpA) are a family of inflammatory rheumatic diseases that commonly affect the spine and entheses and may involve peripheral joints and various extra-articular sites. The group includes axial spondyloarthritis (which comprises non-radiographic axial SpA and radiographic disease traditionally called ankylosing spondylitis), psoriatic arthritis, reactive arthritis, enteropathic arthritis associated with inflammatory bowel disease, and undifferentiated SpA. Genetic predisposition, particularly HLA-B27, is common but not universal.

Clinical features typically include inflammatory back pain starting in young adulthood, an insidious onset, morning stiffness that improves with activity, and reduced spinal mobility. Enthesitis, especially at the Achilles tendon and plantar fascia, and asymmetrical oligoarthritis of the lower limbs are common. Dactylitis and extra-articular manifestations such as anterior uveitis, psoriasis, and inflammatory bowel disease may occur.

Diagnosis relies on history and examination, imaging, and classification criteria such as the ASAS criteria for axial SpA. Imaging evidence of sacroiliitis on MRI or X-ray supports diagnosis. HLA-B27 testing can be supportive, but its absence does not exclude SpA. Other causes of back pain should be excluded.

Treatment emphasizes nonsteroidal anti-inflammatory drugs as first-line, physical therapy and exercise, and management of comorbidities. Conventional DMARDs may help peripheral arthritis but are less effective for axial disease. Biologic therapies, including TNF inhibitors and IL-17 inhibitors, and targeted agents such as JAK inhibitors, are used for various SpA manifestations. Smoking cessation and vaccination are recommended; monitoring for ocular, gastrointestinal, and skin involvement is important.

The course is chronic with variable progression. Early recognition and treatment improve outcomes and quality of life. Prevalence estimates vary; SpA affects about 0.5–1% of the population and is more common in men for axial disease.