Acute bronchitis occurs when areas in the bronchial wall of the tubes carrying air from the windpipe into the lungs become inflamed and swollen. This increases mucus and narrows the passageway, making it hard for people to breathe, according to FamilyDoctor.org. Symptoms of bronchitis include coughing that brings up clear, yellow or green mucus, chest congestion, wheezing, sore throat and fever. Acute bronchitis may last for a few weeks. Chronic bronchitis results from a recurring condition of airway problems.
Viruses
Viral bronchitis often occurs during the winter from the spread of viruses, according to the Merck Manuals Online Medical Library. Colds and the influenza virus set off many cases of acute bronchitis. Pneumonia and whooping cough may also cause acute bronchitis. These viruses can spread through the air or onto a person's hands when coughing. Touching the hands can spread the virus. Chronic sinus infections, allergies and enlarged tonsils and adenoids increase the risk of repeated bronchitis episodes. The body’s defenses fight off the viruses, and more swelling and mucus occurs as a result until the viruses are killed. Symptoms may continue for weeks even after the infection has been cleared.
Irritants
Bacterial or infectious bronchitis stems from an upper respiratory infection that often targets smokers or people who are around smoke. Smokers with chronic lung diseases suffer from repeated episodes of acute bronchitis that can develop into chronic bronchitis. Air pollutants, such as smog and household cleaning products, contribute to the development of bronchitis. Breathing fumes in factories can cause bronchitis. Chemicals that may cause bronchitis include strong acids, ammonia, chlorine, hydrogen sulfide, sulfur dioxide, bromine and some organic solvents. Exposure to mineral and vegetable dusts make people vulnerable to bronchitis, the Merck Manuals notes.
Acid Reflux
Stomach acids that frequently back up into the esophagus and throat can cause bronchitis, the Mayo Clinic explains. Gastroesophageal reflux disease, also called GERD, is a chronic type of heartburn and acid reflux. In people with GERD, a muscle valve in the esophagus becomes weakened and as such, may not close completely once food and beverages enter the stomach. This allows digestive juices to back up from the stomach into the esophagus and produce frequent occurrences of acid reflux. The acids go into the upper airway and increase the risk of inflammation and bronchitis.
