The following factors increase your risk for acute bronchitis.

Risk factors you cannot change

These include:

• Chronic medical conditions, especially lung (pulmonary) diseases such as chronic obstructive pulmonary disease (COPD), cystic fibrosis, or asthma. In this case, acute bronchitis may be a more serious problem and may be treated differently.
• Some conditions that cause immune system problems, such as diabetes and HIV infection. An impaired immune system weakens the body's ability to fight infection.
• A history of recent upper respiratory infection, particularly sinusitis, a cold, or influenza (flu). An upper respiratory infection can spread to the lungs.
• Allergies, such as allergic rhinitis.
• An injury to the chest wall, such as a rib fracture.

Risk factors you can change

These include:

• Smoking or living with someone who smokes. Smoking or breathing secondhand smoke makes the respiratory system less effective at removing organisms from the lower airways.
• Living or working in an area with high levels of air pollution, chemicals, or dust. Breathing in these irritants may make the respiratory system less effective at removing organisms from the lower airways.