What Happens

Acute bronchitis is inflammation of the tubes that carry air to the lungs (bronchial tubes). It is usually caused by a virus and follows an upper respiratory tract infection such as a cold or influenza (flu). The infection moves from the nose, mouth, and throat to the bronchial tubes, causing the tubes to swell and mucus production to increase.

At first, a dry, hacking cough is present. After a few days, the cough may bring up mucus from the lungs. The swollen tubes and increase in mucus may make it more difficult for you to breathe.

See a picture of acute bronchitis.

Most cases of acute bronchitis in otherwise healthy people last only 2 to 3 weeks. But more than 20% of people with acute bronchitis have a cough that lasts more than 4 weeks.²

How soon you get better depends on several things, including:

• Your age and health.
• The organism causing the infection. Acute bronchitis from a viral cause is usually less severe than from a bacterial cause.
• Whether you smoke.

Complications

Most people get better without developing complications. If complications occur, they include:

• Pneumonia. Acute bronchitis that gets worse (increased fatigue, high fever, chest pain, and increased shortness of breath) usually indicates that pneumonia has developed.
• Repeated episodes of bacterial acute bronchitis. This condition commonly occurs in people who smoke and in people with immune system problems, such as HIV infection, cystic fibrosis, or cancer.

If you have a long-term (chronic) respiratory disease, such as asthma, acute bronchitis can make your coughing and wheezing worse and can increase the risk of developing complications. In this case, acute bronchitis is a more serious problem and may be treated differently.

Children and older adults are most at risk for complications.

Children who have repeated bouts of acute bronchitis need to be evaluated to see whether they may have a foreign object in the air passage. Children may also be evaluated for asthma or other respiratory tract problems, such as:

• Cystic fibrosis, an inherited disease that results in the production of thick mucus in the lungs.
• Bronchiectasis, a lung condition in which the airways of the lungs are damaged, get bigger, and are frequently infected. A common symptom is a cough that brings up mucus.
• Allergies, which are an immune system reaction to usually harmless substances. Symptoms include cough and difficulty breathing. Allergic rhinitis (hay fever) is a common allergy.
• Sinusitis, an infection of the mucous membranes that line the inside of the nose and facial sinuses. Symptoms include pain and a chronic cough that produces mucus.
• Adenoiditis, an inflammation of the adenoids, which are small masses of tissue at the back of the nose and throat.