A 40-year old woman presented with pyrexia, productive cough, and bilateral precordial pain. Positron emission tomography (PET)-computed tomography (CT) showed high, diffuse F-18 deoxyglucose accumulation in the tracheal, peribronchial, and bilateral costal cartilage. We diagnosed her with relapsing polychondritis (RP) based on McAdam's criteria. Airway lesions are a major prognostic indicator of RP, and so chronological assessment and control is essential. In this patient, PET-CT accurately reflected both the location and severity of the inflammation and helped to guide treatment decision-making and facilitated early detection of recurrence. However, its high cost is prohibitive to frequent use, making it necessary to comprehensively evaluate serum C-reactive protein levels, bronchoscopy, spirometry, and 3D-CT.