The impact of asthma exacerbations and preventive strategies.

OBJECTIVE: To review the pathophysiologic mechanisms underlying asthma exacerbations, the impact of exacerbations, and both current and future treatment strategies to establish asthma control and reduce the risk of future exacerbations.

RESEARCH DESIGN AND METHODS: Relevant adult data were identified via PubMed, with additional references obtained by reviewing bibliographies from selected articles.

RESULTS: Asthma exacerbations or 'attacks' are acute episodes of progressive worsening of symptoms which occur in patients with all degrees of asthma severity and are an important cause of morbidity and mortality. For patients, these asthma attacks constitute a considerable part of the disease burden in terms of both personal suffering and economic impact. Exacerbations are characterized in part by decreases in expiratory flow or lung function. The pathophysiologic mechanism underlying these changes is likely to be different depending on the specific asthma phenotype. Asthma exacerbations are commonly initiated by upper respiratory tract infections and/or environmental allergens, although there are other known factors which increase the risk of a patient developing exacerbations, such as cigarette smoking. Establishing asthma control and reducing the risk of future exacerbations is the main goal of asthma treatment. Inhaled corticosteroids alone or in combination with long-acting β2-agonists, in addition to other step-up strategies such as leukotriene receptor antagonists and theophylline, are recommended. The anti-immunoglobulin E monoclonal antibody omalizumab should also be considered in difficult-to-treat allergic asthma.

CONCLUSIONS: Despite the currently available treatments, many patients with asthma remain symptomatic and experience exacerbations regardless of disease severity. New therapies, including long-acting anticholinergics, anti-cytokines, and chemoattractant receptor-homologous molecules, are under investigation with some promising results. In addition to increased education and use of self-management plans, these novel therapies are essential to help improve asthma control and reduce exacerbation risk.