The review aimed to explore the contribution to peripheral airway impairment in pediatric asthma, mainly due to the inaccessibility to evaluation by noninvasive techniques widely available.

Emerging evidence suggests that small airways are affected from the early stages of the disease in childhood-onset asthma. Conventional lung function measurement, using spirometry, cannot sensitively evaluate small airway function and may become abnormal only once there is a significant burden of disease. Chronic inflammation and dysfunction in the small airways, is detected with new advanced techniques, are risk factors for asthma persistence, asthma severity, worse asthma control, and loss of pulmonary function with age, both in adults and children. Knowing the extent of central and peripheral airway involvement is clinically relevant to achieve asthma control, reduce bronchial hyper-responsiveness, and monitor response to asthma treatment.

This review focuses on the role of minor airway dysfunction in pediatric asthma development and control. It addresses how the use of new diagnostic techniques available in outpatient clinical settings, namely impulse oscillometry and multiple breath washout, could help in the early detection of minor airway impairment in children with preschool wheezing and school-age asthma and potentially guide asthma treatment.