Causes of chronic bronchitis: it develops in the continual presence of irritants, usually tobacco smoking or exposure to second hand smoke, food allergies, environmental irritants especially dust, pollen, animal dander or mold, cold damp and foggy weather.

The root causes of bronchitis: acute bronchitis is the deep, wet or dry cough that comes on and lingers after an infection e.g. cold, sinusitis and flue. Its causes are food or environmental allergies, causing excess mucus in the lungs, and viral infection. The symptoms of acute and chronic BRONCHITIS include a cough that may start out dry but that turns deep and productive, with thick clear or yellow mucus. It usually follows a viral infection, long bouts of acute bronchitis that recur frequently, a persistent, constant cough that is worse upon waking, breathlessness and wheezing.