Not all patients with “difficult-to-control” asthma have “severe asthma”. Many of them have either an incorrect diagnosis, or mild-moderate asthma with unrecognised aggravating factors, or are non-compliant with prescribed therapy.
For a diagnosis of severe asthma, it is necessary to confirm the diagnosis of asthma, to evaluate and treat endogenous and exogenous aggravating factors, and to closely follow the patient for ≥6 months.
Severe asthma is a heterogeneous condition with different phenotypes. Defining clinical phenotypes is necessary to improve understanding of underlying mechanisms, to help guide current treatment and to provide clues for novel therapeutic interventions.
Despite intensive multi-drug treatment with high-dose inhaled and oral corticosteroids, many patients with severe asthma remain uncontrolled. There is an urgent need for new, more-effective treatments.
To help the reader distinguish between “difficult-to-control”, “refractory” and “severe” asthma.
To discuss the initial approach to and assessment of a patient with difficult-to-control asthma.
To inform the reader how to recognise different clinical phenotypes of severe asthma.
To outline management strategies and discuss treatment modalities.
Summary “Severe asthma” refers to asthma that remains difficult to control despite intensive multidrug therapy, extensive assessment and management of comorbidity, and long-term observation by an asthma specialist.
The three main clinical phenotypes of severe asthma include asthma with frequent severe exacerbations, asthma with chronic airflow limitation, and steroid-resistant asthma.
Many patients with severe asthma are oral-steroid dependent. Classical steroid-sparing drugs (gold, methotrexate, cyclosporin) are only weakly effective and have unacceptable side-effects. Monoclonal antibodies against immunoglobulin (Ig)E and tumour necrosis factor (TNF)-α have shown clinical benefit in subgroups of patients with severe asthma, and large studies are under way to confirm these promising findings.
- ©ERS 2006
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