Summary

• An inflammatory arthritis predominantly affecting the sacroiliac joints and axial spine.
• Classified as a seronegative spondyloarthropathy. The seronegative spondyloarthropathies (including psoriatic arthritis, enteropathic arthritis, and reactive arthritis) are a heterogenous group of conditions with overlapping clinical manifestations and association with the gene HLA-B27.
• Inflammatory back pain is the hallmark clinical feature. This is defined as back pain that is of insidious onset, is worse in the morning, and improves with exercise.
• A positive response to non-steroidal anti-inflammatory drugs (NSAIDs) is characteristic of most patients.
• Physiotherapy and NSAIDs are the cornerstone of treatment. In refractory patients, tumour necrosis factor (TNF)-alpha inhibitors play a key role.