Adult-onset chronic nonbacterial osteitis mimicking refractory axial psoriatic arthritis: successful treatment with combined IL-1/IL-17 inhibition: a case report and brief literature review

We report a 46-year-old man with palmoplantar pustular psoriasis and severe axial inflammation who was initially diagnosed with refractory axial psoriatic arthritis. Despite sequential treatment with multiple biologic and targeted therapies, disease activity persisted. Reassessment based on anterior chest wall involvement, characteristic positron emission tomography/computed tomography findings, human leukocyte antigen B27 negativity, and exclusion of infectious, malignant, and monogenic autoinflammatory disorders supported a diagnosis of adult-onset chronic nonbacterial osteitis (CNO). The patient showed a marked clinical, laboratory, and imaging response to interleukin (IL)-1 blockade, and sustained disease control was achieved with combined IL-1/IL-17 inhibition. This case highlights the diagnostic challenges of adult CNO and suggests a potential role for dual cytokine inhibition in refractory disease. A brief literature review on current treatment options is provided.