(HealthDay News) – There is increasing evidence that the small airways contribute significantly to the clinical expression and severity of asthma, according to research published online Nov. 9 in Allergy.

Maarten van den Berge, MD, PhD, from the University of Groningen in the Netherlands, and colleagues reviewed the clinical relevance of small airway disease and its implications for the treatment of asthma.

The researchers found that, based on increasing evidence, small airway disease was shown to be associated with symptoms, disease severity, and bronchial hyper-responsiveness. When developing inhaled treatments for small airway disease, particle size and distribution are of key importance. A higher drug deposition into the peripheral lung has been enabled by the availability of hydrofluoroalkane-134a (HFA)-ciclesonide, HFA-beclomethasone dipropionate, and other small-particle aerosols. These small-particle aerosols potentially provide additional clinical benefits vs. large-particle treatment. Since conventional spirometry mainly reflects large airway function, improved methods are needed to assess small airway disease and its response to treatment.

“Overall, the emerging evidence from recent years suggests an important role of the small airways in asthma because they contribute to the clinical expression of the disease and responsiveness to treatment with small- or large-particle inhaled drugs,” the authors write. “More research is now urgently needed to answer the many remaining questions which currently impact the treatment for asthma and obstructive airway diseases in general.”

Several authors disclosed financial ties to the pharmaceutical industry.

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