Purpose of review: To review the latest guidelines on severe asthma.
Recent findings: An updated definition of severe asthma is provided together with the evaluation steps necessary to reach a diagnosis of severe asthma. The importance of phenotyping is emphasized, and recommendations are provided for therapies specifically directed for severe asthma.
Summary: Severe asthma is widely recognized as a major unmet need. It is defined as asthma that requires treatment with high-dose inhaled corticosteroids and a second controller and/or systemic corticosteroid to prevent it from becoming 'uncontrolled' or that remains 'uncontrolled' despite this therapy. Severe asthma is a heterogeneous condition that consists of phenotypes such as eosinophilic asthma. More phenotypes need to be defined. Evaluation of the patient referred to as having severe or difficult-to-control asthma must take into account adherence to treatment, comorbidities and associated factors including side effects from therapies. These need to be addressed. Recommendations on the use of sputum eosinophil count and exhaled nitric oxide to guide therapy are presented. Treatment with anti-IgE antibody, methotrexate, macrolide antibiotics, antifungal agents and bronchial thermoplasty is reviewed and recommendations made. Research efforts into phenotyping of severe asthma will provide both biomarker-driven approaches and newer effective therapies to severe asthma management.