What causes bronchiectasis?

There are numerous causes for bronchiectasis. However, in approximately 50% of cases, an underlying cause is not found (King et al 2006). In these cases the disease is often found in the lower lobes. It is likely though that “ideopathic” bronchiectasis is relatively rare but there are not currently robust or readily available tests of many subtle abnormalities of immune function for the many of these cases to be classified.

It is ideal to identify the cause of bronchiectasis where possible, to target appropriate disease management strategies. These strategies may be associated with reducing the progression of bronchiectasis.

Bronchiectasis may present as a primary lung manifestation of the conditions listed below, which can cause chronic inflammation resulting from an abnormality of anatomy, immunity or function.

Secondary bronchiectasis is more common and may occur as a complication of other lung diseases as a consequence of airway distortion, traction and ultimate damage in relation to conditions including COPD, emphysema, bronchitis, bronchiolitis and interstitial lung disease.

Post infection:


Pertussis (whooping cough)

Viral (measles, adenovirus, influenza virus)

Mycobacterial (tuberculosis and atypical NTM)

Primary or secondary immune deficiency:

Immunoglobulin G subclass deficiency – for more information go to Immune Deficiency Foundation


Lung and bone marrow transplantation



Human T-Lymphotropic Virus 1 (HTLV-1)

Asthma and fungal allergy:
Mucociliary dysfunction:
Recurrent small volume aspiration:

Gastro-oesophageal reflux

Poor dentition/recurrent oral infection

Bronchial obstruction:

Inhalation of foreign objects such as peanuts


Airway compression

Lymph node

Systemic inflammatory diseases:

Rheumatoid arthritis

Sjögren’s Syndrome

Inflammatory bowel disease


Structural lung disease:

Chronic obstructive pulmonary disease


Interstitial lung disease

Pulmonary fibrosis and pneumoconiosis:
Treatable causes of bronchiectasis:

Immune deficiency


Mycobacterial infection

Airway obstruction

Inflammatory bowel disease

Rheumatoid arthritis