Bronchiectasis generally results from lung infections. As the infection enters the lung, the bronchi widen and thicken. Bronchiectasis can be acquired later in life or it can be congenital. Besides infections, obstructions in the airways, immunological problems, or fibrosis in the lung tissue can also lead to bronchiectasis.

Factors that can lead to bronchiectasis include:

* Lung infections such as whooping cough, pneumonia, or tuberculosis
* Airway obstructions
* COPD
* Cystic fibrosis
* Autoimmune diseases
* HIV
* Diabetes
* Rheumatic or connective tissue diseases
* Systemic diseases such as Crohn's disease and ulcerative colitis