Bronchitis is a serious but common inflammatory condition of the lungs. Inflammation of the lungs causes redness, swelling, mucus production, and pain. There are two types of bronchitis: acute and chronic. In acute bronchitis, inflammation occurs as a result of a cold, sore throat, or viral infection. Symptoms include fever, headache, fatigue, and a dry cough that progressively becomes productive. Prolonged acute bronchitis that continues for several weeks often develops into pneumonia. In chronic bronchitis, inflammation occurs as a result of exposure to tobacco smoke or other irritants. Symptoms include fever, headache, fatigue, severe coughing, and phlem. Prolonged chronic bronchitis with coughing that lasts over many years can lead to permanent damage of lung tissue causing disability or even death.