Severe asthma affects 5 to 10% of the asthma population but consumes a disproportionate amount of the global asthma budget (~50%) due to unscheduled health care utilization in primary care, hospitalizations due to severe exacerbations, and the costs of pharmacotherapy. A key challenge in managing severe asthma is to identify appropriate groups of patients that will respond best to existing and evolving therapies. Recent advances in our understanding of how to classify severe asthma using multivariate taxonomical approaches have provided a unique model of a stratified medicines approach. For example, patients with inflammation-predominant asthma with eosinophils benefit from both inhaled and oral corticosteroids as well as targeted biologics such as anti-interleukin (IL)-5, all of which significantly reduce asthma exacerbations. On the other hand, patients with noneosinophilic neutrophilic asthma may be more suitable for steroid down-titration and therapeutic trials of antineutrophilic agents such as macrolide antibiotics. A similar paradigm can be applied to other domains in severe asthma such as airway hyperresponsiveness, which may now be treated with the first mechanical therapy in airways disease (bronchial thermoplasty). At the same time it is important for the clinician to recognize and treat comorbid factors that make asthma difficult to manage such as poor adherence to medication, rhinosinusitis, and psychological comorbidity. Therefore it is of vital importance to develop a multidisciplinary approach to the management of severe asthma that is best applied within specialist centers with experience and wider access to national and international severe asthma networks.
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