Young onset chronic inflammatory back pain: A diagnostic dilemma between axial spondylitis and diffuse idiopathic skeletal hyperostosis.

Diffuse idiopathic skeletal hyperostosis (DISH) and axial spondyloarthritis (axSpA) share similarities in both clinical presentation and radiological findings, making the diagnostic process challenging. We report the case of a 30-year-old male with a long-standing history of back pain with an initial diagnosis of young-onset DISH. However, a diagnosis of axSpA was ultimately pursued based on his age and clinical presentation. This was further supported by improvement in both Ankylosing Spondylitis Disease Activity Score with Erythrocyte Sedimentation Rate (ASDAS-ESR) and Ankylosing Spondylitis Disease Activity Score with C-Reactive Protein (ASDAS-CRP) scores at his 6- and 12-month follow-ups on ixekizumab. Early and accurate diagnosis of axSpA, followed by appropriate treatment, is essential in preventing complications and improving patient outcomes.