Unrecognized small airway dysfunction in otherwise mild, well-controlled asthmatics increases exacerbation risk

Published online July 9, 2025

Although current recommendations for asthma management and treatment based on established guidelines have generally proven effective, many asthmatic patients with mild, well-controlled disease continue to experience loss of symptom control, increased exacerbation frequency, and associated accelerated lung function decline. A possible explanation for increased exacerbations in patients with mild, well-controlled disease is the failure to recognize that small airway dysfunction (SAD) represents major sites of inflammation and obstruction in this clinical phenotype. SAD may be associated with increased risk of loss of control and exacerbations.  SAD determined by oscillometry, which, unlike spirometry, is effort independent requiring only normal breathing effort, has been shown to be useful in the diagnosis and management of asthma. Although mild, well-controlled asthma occurs in up to 50% to 75% of all patients with asthma; it can be associated with fatal exacerbations, even if the patients are adherent to medication. Thus, there is a need for an early warning marker to predict exacerbation risk, which if treated early could prevent severe asthma complications. The purpose of our study was to evaluate the association between  SAD evaluated by oscillometry, and a history of exacerbations in adult patients with mild, well-controlled asthma.  

In this study, reported in The Journal of Allergy and Clinical Immunology: In Practice, Galant and associates found that in mild, well-controlled asthma, SAD is common and is associated with a greater risk of previous exacerbations, independent of other known risk factors. The data also showed that treatment with small particle size, extra fine inhaled corticosteroids, was associated with decreased SAD as well as decreased SAD associated previous exacerbations. The authors concluded that small airway dysfunction is associated with more frequent exacerbations in patients with mild, well-controlled asthma and could be a useful clinical marker to direct therapy.

The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.

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