Bronchiectasis and asthma: a dangerous liaison?

Recent studies demonstrate that the combination of asthma and bronchiectasis is a common phenomenon, leading to a more severe course of asthma with frequent exacerbations. The mechanisms underlying the association between these two diseases are not well understood; however, they share common clinical and immunological features, as well as numerous comorbidities. The aim of this review was to examine and analyze the results of studies focusing on concomitant asthma and bronchiectasis. Methods. A literature search in the PubMed, MedLine databases was conducted using the following key terms: bronchiectasis in asthma, association between asthma and bronchiectasis, comorbidities in asthma, severe asthma, treatment of asthma and bronchiectasis. The publication date was not limited. Results. Asthma and bronchiectasis share overlapping symptoms, similar comorbid conditions, and etiopathogenetic mechanisms. The coexistence of these two diseases may form a characteristic phenotype with a more severe course of asthma. The “asthma + bronchiectasis” phenotype is characterized by more severe bronchial obstruction, frequent exacerbations, and longer hospitalizations as compared to asthma alone. Patients with asthma and chronic rhinosinusitis have an especially high risk of developing bronchiectasis. Recently, bronchiectasis has been viewed as an inflammatory, rather than purely infectious, disease, highlighting the complexity of its pathophysiology. Bronchiectasis with high eosinophil levels is of particular interest. The “asthma + bronchiectasis” phenotype reflects the overlap of eosinophilic and neutrophilic inflammatory mechanisms, leading to airway remodeling, while microbiota dysbiosis exacerbates this inflammation. This creates a vicious cycle of airway inflammation and damage. Early detection of bronchiectasis with high-resolution computed tomography in patients with severe asthma is essential for initiating appropriate therapy for both diseases. This approach improves symptom control and reduces the frequency of exacerbations and infections. Conclusion. Bronchiectasis is a common comorbid condition in patients with asthma. The combination of these two diseases constitutes a distinct phenotype characterized by more frequent chronic infections and increased disease severity. Patients with the “asthma + bronchiectasis” phenotype require an individualized approach to optimize treatment and effectively address this complex comorbidity.