Airway remodelling and small airways dysfunction in asthma

A once underrecognised contributor to the disease, the small airways are now acknowledged as the primary site of airflow limitation in asthma. Small airways disease is present in the majority of asthmatic patients across all disease severities, and predicts exacerbations, symptoms and quality of life. Although studying this distal region of the lung remains challenging, a variety of intriguing techniques have emerged in recent years. Persistent airflow limitation, the clinical manifestation of repeated cycles of inflammation, injury and dysregulated repair that leads to airway remodelling, is associated with small airways disease. New asthma therapies appear to modulate and possibly even reverse airway remodelling. Early recognition of small airways dysfunction and initiation of targeted therapies may alter the course of disease.