Appraising the small airways in asthma

Curr Opin Pulm Med. 2012 Jan;18(1):23-8. doi: 10.1097/MCP.0b013e32834dd8c2.


Purpose of review: The small airways play an important yet poorly targeted role in asthma pathophysiology, leading to increased morbidity in asthma patients. Assessing inflammation and remodeling in these airways, determining the contribution of small airways to lung dysfunction and enhancing drug delivery to the distal regions of the lung remain challenging. The purpose of this review is to highlight recent advances in our understanding of small airways involvement in asthma.

Recent findings: Inflammation in the small airways can be evaluated through exhaled gas measurements, most often nitric oxide. However, additional exhaled biomarkers have recently been described. Considerable infiltration of mast cells in the distal lung and extensive structural changes to the small airways have also been demonstrated. Advances have been made in the functional assessment of small airways, particularly in the measurement of small airway compliance and ventilation defects and in studies investigating the impact of small particle inhaled corticosteroid treatment on lung function.

Summary: Experimental assessments of small airways inflammation, remodeling and function have provided novel insights into the importance of the distal regions of the lung in asthma pathology. Further advances in drug delivery to the small airways have the potential to improve asthma control.

Publication types

  • Review

MeSH terms

  • Adrenal Cortex Hormones / therapeutic use*
  • Airway Remodeling* / drug effects
  • Airway Resistance
  • Anti-Inflammatory Agents / therapeutic use*
  • Asthma / drug therapy
  • Asthma / pathology*
  • Asthma / physiopathology
  • Humans
  • Immunohistochemistry
  • Inflammation
  • Lung / drug effects
  • Lung / pathology*
  • Lung / physiopathology
  • Nitric Oxide
  • Respiratory Function Tests


  • Adrenal Cortex Hormones
  • Anti-Inflammatory Agents
  • Nitric Oxide