Heterogeneity in Severe Asthma

People with severe asthma make up a small proportion of the total number of people with asthma. However, despite being relatively uncommon, severe asthma utilizes the majority of asthma-related health-care expenditures. A personalized medicine approach to severe asthma has been suggested as severe asthma is difficult to treat and the population with severe asthma is very heterogeneous. In this chapter we discuss some of the ways in which people with severe asthma can be sub-classified. This includes a discussion of differences between children and adults, types of airway inflammation seen, and clinical characteristics. Understanding heterogeneity will lead to improved understanding of the pathophysiology underpinning the clinical presentation. However, future work will need to focus on characterizing subtypes of severe asthma in a fashion that has direct relevance for treatment and outcomes.