The overlap of bronchiectasis and immunodeficiency with asthma.

Bronchiectasis should be considered as a differential diagnosis for, as well as a comorbidity in, patients with asthma, especially severe or long-standing asthma. Chronic airway inflammation is thought to be the primary cause, as with chronic or recurrent pulmonary infection and autoimmune conditions that involve the airways. Consequently, immunodeficiencies with associated increased susceptibility to respiratory tract infections or chronic inflammatory airways also increase the risk of developing bronchiectasis. Chronic bronchiectasis is associated with impaired mucociliary clearance and increased bronchial secretions, leading to airway obstruction and airflow limitation, which can lead to exacerbation of underlying asthma or increased asthma symptoms.