Relapsing Polychondritis With Severe Airway Involvement Mimicking Refractory Asthma: A Diagnostic Challenge.

Relapsing polychondritis (RP) is a rare immune-mediated disorder that can cause severe tracheobronchial involvement and life-threatening airway compromise. We present a diagnostically challenging case of a 30-year-old non-binary patient whose progressive respiratory symptoms were initially attributed to severe refractory asthma. Despite repeated courses of systemic corticosteroids and escalation of asthma-directed therapy, they developed recurrent breathlessness, wheeze, and inspiratory stridor. Pulmonary function testing demonstrated severe fixed airflow obstruction with minimal bronchodilator reversibility and a flow-volume loop suggestive of central airway obstruction. Serial CT imaging subsequently demonstrated progressive smooth thickening and narrowing of the tracheobronchial tree, with relative sparing of the posterior membranous wall and no significant pulmonary parenchymal disease. These findings, together with the clinical course, exclusion of important alternative diagnoses, and multidisciplinary assessment by respiratory, rheumatology, radiology, and tertiary airway specialists, supported a clinicoradiological diagnosis of airway-dominant RP. Despite high-dose corticosteroids and cyclophosphamide followed by maintenance immunosuppression, the patient continued to experience severe airway compromise and recurrent respiratory symptoms. This case highlights the importance of considering RP in patients with treatment-refractory asthma-like symptoms, particularly when inspiratory stridor, fixed airflow obstruction, and progressive tracheobronchial abnormalities are present. Early recognition of central airway involvement and multidisciplinary assessment are essential to minimise irreversible airway damage.