Ultrasonography of Auricular Cartilage Is a Useful Tool for Diagnosing and Monitoring Disease Activity in Relapsing Polychondritis

Aim To assess the clinical utility of ultrasonography in the diagnosis and monitoring of disease activity in relapsing polychondritis (RP). Methods Auricular and nasal chondritis of 6 patients with RP were assessed by ultrasonography before treatment initiation. Changes in the ultrasonographic and clinical findings and serum inflammatory markers were longitudinally assessed. Ultrasonography was also performed in 6 patients with repeat ear trauma, 6 patients with auricular cellulitis and 6 healthy controls for comparison among groups. Results In all cases of RP, ultrasonographic findings before treatment revealed low-echoic swollen auricular and nasal cartilage and perichondral soft-tissue with increased power Doppler signals (PDS) corresponding to biopsy findings. After 2-month treatment with prednisolone (PSL) combined with methotrexate, clinical and serum inflammatory markers were completely resolved. Although swollen perichondral soft-tissue, cartilage and PDS on auricular ultrasonography were also significantly improved, PDS remained in 2 of 6 cases, which showed flare early after tapering PSL. Finally, ultrasonographic findings of RP were substantially differentiated between patients with repeat trauma and cellulitis and healthy controls based on the thickness of soft tissue around the cartilage, PDS and subperichondral serous effusion. Conclusion Assessment of RP lesions by ultrasonography is useful for the evaluation of cartilaginous lesions and monitoring of disease activity, especially when considering the treatment response and the timing of drug tapering.