1. Etiology of asthma exacerbations
Annemarie Sykes, MBBS, MSc, Sebastian L. Johnston, MBBS, PhD 
Journal of Allergy and Clinical Immunology 
Volume 122, Issue 4, Pages (October 2008)
DOI: /j.jaci
Copyright © 2008 American Academy of Allergy, Asthma & Immunology Terms and Conditions

2. Fig 1
Cause of asthma exacerbations. Viral infection is the predominant cause of asthma exacerbations, and synergy exists between allergen sensitization and viral infection. A link between viral infection and atypical bacteria is increasingly recognized.
Journal of Allergy and Clinical Immunology  , DOI: ( /j.jaci )
Copyright © 2008 American Academy of Allergy, Asthma & Immunology Terms and Conditions