Bronchitis is an inflammation of the main air passages (bronchi) to the lungs. It causes a cough, shortness of breath and chest tightness. Coughing often brings up yellow or greenish mucus. There are two main types of bronchitis: acute and chronic.
Acute bronchitis is often caused by the same viruses that cause colds. It usually starts as a sore throat, runny nose or sinus infection, then spreads to the airways. It can cause a lingering dry cough, but it usually goes away on its own.
Chronic bronchitis is one type of COPD (chronic obstructive pulmonary disease). The inflamed bronchi produce a lot of mucus. This leads to cough and difficulty getting air in and out of the lungs. Cigarette smoking is the most common cause. Breathing in other fumes and dusts over a long period of time may also cause chronic bronchitis. Treatment will help alleviate symptoms, but chronic bronchitis is a long-term condition that keeps coming back or never goes away completely.