Spondyloarthritis (SpA) group, which causes similar clinical findings and is treated similarly, is evaluated in two subgroups as axial and peripheral according to clinical characteristics. It is named as radiographic axial SpA if sacroiliitis is shown on X-ray, and if sacroiliitis detected on magnetic resonance imaging (MRI) but X-ray normal; it is considered to be a non-radiographic axial SpA. Diagnosis is psoriatic arthritis (radiographic or non-radiographic) if psoriasis associated with SpA; enteropathic arthritis (radiographic or non-radiographic) with inflammatory bowel disease; It is considered as reactive if occurred after an infection. If there is no comorbid disease and radiographically proven sacroiliitis, it is named as ankylosing spondylitis (AS).

The most basic diagnostic tool of axial SpA is the history of inflammatory back pain. The search for sacroiliitis by direct radiography or MRI and HLA-B27 are other diagnostic procedures. The treatment of AS and axial SpA begins with physical exercise and prevention of exposure to tobacco products. Non-steroidal anti-inflammatory drugs, sulfasalazine, and biological treatment agents are used in medical treatment, respectively.