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The term ‘seronegative arthritis’ has, in recent years, been reinterpreted as ‘spondyloarthritis’ (SpA), a family of conditions with common pathological lesions and genetic basis. The family comprises axial SpA (axSpA)/ankylosing spondylitis, psoriatic arthritis, reactive arthritis, enteropathic arthritis as well as undifferentiated and juvenile forms. Inflammation at the entheses is characteristic of SpA, often occurring at the joints in the spine as well as within peripheral joints and, in cases of psoriatic arthritis, at the nail attachments. Recently, new classification criteria have been introduced for axSpA that reflect the whole spectrum of ankylosing spondylitis and psoriatic arthritis. Recent genetic work has shed further light on the possible role of human leukocyte antigen-B27 and also pointed to important potential roles for other genes including ERAP-1 and the interleukin 23 receptor. Pathogenic roles for both commensal and infective micro-organisms are proposed but clear conclusions about causation cannot yet be drawn. In addition to spinal and peripheral joint lesions, SpA is associated with extra-articular lesions, notably acute anterior uveitis, inflammatory bowel disease and psoriasis and important comorbidities, notably cardiovascular disease and osteoporosis. Treatments of axial and peripheral disease are increasingly tailored according to objective- and patient-reported outcome measures. In all conditions, the range of therapeutic options includes physical exercise, non-steroidal anti-inflammatory drugs, corticosteroids and tumour necrosis factor (TNF) inhibitors. Disease-modifying antirheumatic drugs may be effective for the peripheral disease but not for the axial disease. Patient management should also take into account the actual and potential extra-articular lesions and the possible comorbidities. The introduction of TNF-inhibitor drugs for the treatment of axSpA and psoriatic arthritis has dramatically improved the prognosis for these conditions with the promise of considerable further developments in the foreseeable future.