What Causes Bronchiectasis?

Bronchiectasis is caused by injury to the lower airways. This injury may be caused by another disease, including:

• Cystic fibrosis, which leads to almost half of the cases of bronchiectasis in the United States.
• Severe pneumonia.
• Whooping cough (uncommon because most people are now vaccinated against it).
• Tuberculosis (TB) and other similar infections.
• Immunodeficiency disorders, such as HIV infection and AIDS.
• Allergic bronchopulmonary aspergillosis, an allergic reaction to a fungus called aspergillus that causes swelling in the airways.
• Kartagener's Syndrome, a rare inherited disease that involves the cilia (sil'-ee-ah). These are small hair-like structures that line your airways and normally clear out mucus.
• Other disorders that affect the function of the cilia.

Other conditions that can injure the lower airways and lead to bronchiectasis include:

• Blockage of your airways by a growth or a noncancerous tumor
• Blockage of your airways by something you inhaled—for example, a piece of a toy or a peanut that you inhaled when you were a child
• Fungal infections.