Bronchitis is an inflammation of the air passages between the nose and the lungs, including the trachea (windpipe) and the larger air tubes of the lung that bring air in from the trachea (bronchi). Bronchitis can either be of brief duration (acute) or a long-term disease (chronic).

Acute bronchitis is most prevalent in winter. It usually follows a viral infection, such as a cold or the flu, and can be accompanied by a secondary bacterial infection. Acute bronchitis usually begins with the symptoms of a cold, such as a runny nose, sneezing, and dry cough. However, the cough soon becomes deep and painful. Coughing brings up a greenish yellow phlegm or sputum. These symptoms may be accompanied by a fever of up to 102°F (38.8°C). Wheezing after coughing is common.

In uncomplicated acute bronchitis, the fever and most other symptoms disappear after three to five days...