The Link between Asthma and Bronchiectasis: State of the Art.

The nonrecognition of asthma-associated comorbidities is often responsible for the therapeutic failure and the worsening of symptoms, and it is associated with frequent exacerbations, higher disease severity, and increased health costs. Bronchiectasis, one of the most frequent asthma-associated comorbidities, can increase airways inflammation and exacerbation rates and cause respiratory functional impairment. The aim of this article is to review the interactions between bronchiectasis and asthma, in order to better identify patients in the overlap between the 2 diseases and to select an "ad hoc" therapy. A literature search on PubMed/MEDLINE was performed using the following search terms: bronchiectasis in asthma, the association between asthma and bronchiectasis, comorbidities in asthma, and severe asthma. This review analyzed the following items: incorrect or underestimated diagnosis of asthma and bronchiectasis, prevalence of bronchiectasis in asthma, the impact of bronchiectasis in asthma, radiological imaging features of the 2 diseases, etiopathogenesis, and common causes (such as gastroesophageal reflux disease, immune deficits, chronic rhinosinusitis and allergic bronchopulmonary aspergillosis, and treatment of asthma and bronchiectasis). The concomitant presence of bronchiectasis and asthma should be suspected and investigated in patients with severe asthma, frequent exacerbations, and not responding to standard therapy. This clinical phenotype, characterized by a more severe disease, worse outcomes, and functional decline, must be readily recognized in order to choose the most appropriate therapeutic approach, able to potentially improve the management of bronchial asthma, to prevent the onset of exacerbations as well the functional decline, and to reduce health costs.