How to define severe asthma?
Severe asthmatics have:
- poor control despite high doses of inhaled corticosteroids with or without systemic corticosteroids
- persistent symptoms and/or recurrent exacerbations
How common is severe asthma?
5-10% of the asthmatic population falls within the category of severe asthma.
Patients with severe asthma are a heterogeneous group (asthma is not one diseases).
Patients should be investigated to:
- confirm the diagnosis (may be "not asthma at all")
- exclude alternative diagnoses ("not asthma at all")
- identify comorbidities ("asthma plus")
- evaluate treatment adherence and side-effects from medications
Severe asthma - differential diagnosis and management (click to enlarge the image):
Optimization of asthma medications and monitoring the control and pattern of asthma usually takes place over a period of 6 months.
In patients with confirmed severe refractory asthma, further evaluation is needed of:
- detailed lung function, of airway and lung structure using high resolution computed tomographic (HRCT) scanning
- airway inflammatory processes and biomarkers using induced sputum or bronchial biopsies
Patients with severe asthma are best investigated and managed with a multidisciplinary team.
Severe asthma consists of different phenotypes that need defining.
Transcriptomics and proteomics can improve classification and understanding of severe asthma, with the ultimate hope of finding more effective treatments and a step towards personalized medicine.
The investigation of severe asthma to define phenotypes. Gibeon D, Chung KF. Clin Exp Allergy. 2012 May;42(5):678-92. doi: 10.1111/j.1365-2222.2012.03959.x.