What Is Bronchitis?

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Bronchitis is inflammation and irritation of the bronchial tubes, which are the airways in your lungs. If you have bronchitis, thick mucus may form in your airways, possibly making it difficult to breathe.

Acute bronchitis is caused by a viral respiratory infection, and it may be contagious. However, it usually resolves on its own within days or weeks. Chronic bronchitis, on the other hand, is a lung disease, not an infection, and is not contagious.

Normal Lungs vs. Bronchitis
Verywell / Emily Roberts

Bronchitis Symptoms

The symptoms of acute bronchitis and chronic bronchitis are similar. Acute bronchitis begins during or shortly after a cold, while chronic bronchitis develops over months or years, often due to smoking.

Acute Bronchitis

Acute bronchitis is a short-term problem that can develop when you have a respiratory infection. Normally, acute bronchitis develops soon after initial symptoms of a respiratory infection, which can include a sore throat, a stuffy or a runny nose, headaches, fevers, and fatigue. 

Acute bronchitis can last for weeks, and often resolves on its own.

Symptoms of acute bronchitis include:

  • Frequent coughing
  • Coughing up watery or thick mucus, often described as sputum, which is saliva mixed with mucus
  • Wheezing when you breathe
  • Aching of your chest muscles from persistent coughing

Chronic Bronchitis

Chronic bronchitis is a long-term condition that is characterized by recurrent, often daily, symptoms that last for months at a time. Chronic bronchitis is primarily caused by cigarette smoking, second-hand smoke, air pollution, and environmental chemicals. 

Allergies and respiratory infections can make you more likely to develop chronic bronchitis, and they can exacerbate the condition. If you have chronic bronchitis, you are also more likely to develop recurring lung infections.

Symptoms of chronic bronchitis include:

  • A long-term cough
  • Coughing up mucus
  • Coughing up blood
  • Breathing that takes effort
  • Frequent clearing of your throat
  • Pain throughout the chest, which is usually worse with breathing
  • Shortness of breath which is worse with activity, but may be present at rest
  • Your cough can be exacerbated by cold weather, dampness, and things that irritate the lungs, such as fumes or smoke


There are a number of known causes of bronchitis. Usually, if you are diagnosed with bronchitis, your medical team can identify the cause. Acute and chronic bronchitis have different triggers, and both are due to an inflammatory reaction in the bronchi, which is accompanied by an overproduction of mucus. The inflammation and mucus cause obstruction of the bronchi, which results in the coughing, shortness of breath and wheezing that is characteristic of bronchitis. 

The most common causes of acute bronchitis are brief episodes that trigger inflammation of the bronchi and typically resolve fairly well within a few weeks. Viral infections are the most common causes of acute bronchitis, though other infections can lead to as well. Inhalation of chemicals can also trigger acute bronchitis as can fungal or parasitic infections (rarely). 

Chronic bronchitis is usually caused by recurrent toxin exposure over a long period of time, which results in an inflammatory response. The most common cause of chronic bronchitis is smoking. Some people develop chronic bronchitis as the result of occupational exposure to environmental pollution, which can occur in an indoor or an outdoor setting, or contact with industrial chemicals. 


A diagnosis of bronchitis is based on your medical history, environmental and occupational exposure, and smoking history. Diagnostic tests can help support the diagnosis of bronchitis and can rule out other causes of your cough.

Before an appointment with your doctor, you can use our Doctor Discussion Guide below to read up on common terms and questions that may come up during that conversation.

Bronchitis Doctor Discussion Guide

Get our printable guide for your next doctor's appointment to help you ask the right questions.

Doctor Discussion Guide Old Man

Medical History

If you have a persistent, productive cough lasting for a few weeks, you may have acute bronchitis. If you have had recurrent episodes of daily coughing persisting for at least three months at a time for two years in a row, you might have chronic bronchitis.

Diagnostic Tests

Several diagnostic tests can help in the diagnosis of bronchitis. You will probably not need all of these, but your doctor will determine which tests are required based on the certainty of your diagnosis and whether your breathing is impaired. 

  • Chest X-ray: This test may identify other problems, such as pneumonia.
  • Complete blood count: A blood count can show signs of infection.
  • Sputum culture: A sputum culture can grow bacteria or other organisms that may require antibiotics or other medical treatment
  • Pulmonary function tests (PFTs): If you have chronic bronchitis, your lung function may not be optimal. If you have acute bronchitis, it is unlikely that you would have abnormal PFTs. This test requires your cooperation as you breathe into a device that measures your respiratory abilities, but it is not an invasive test. PFTs can help your doctors determine the degree of impact bronchitis has had on your lung function, which can help direct your treatment. 
  • Pulse oximetry: This is a quick test which uses a small electronic device placed on your finger. A pulse oximetry test is a screening test that can measure the concentration of oxygen in your blood. This test would only be abnormal if you have severe lung disease. 
  • Arterial blood gas test: This is a blood test in which blood is taken from your artery, not your vein, which is where you normally have your blood drawn for a complete blood count. An arterial blood gas may be slightly more uncomfortable than getting blood drawn from your vein. Normally, your arterial blood will be obtained from an artery in your wrist. This test provides a more accurate analysis of your oxygen concentration, which is a better reflection of your pulmonary function than a pulse oximetry test. 


The main goals in the treatment of bronchitis are to keep the airways clear of inflammation and mucus so they can function properly.

Avoiding things that can exacerbate bronchitis, such as fumes or lung infections, can prevent further disability. 

Treatment methods include:

Avoidance of Smoke Inhalation

Avoiding smoke from cigarettes and cigars is important if you have bronchitis, as smoke can exacerbate the symptoms of acute bronchitis, and it can make chronic bronchitis worse. Secondhand smoke is also an irritant. 

Smoking causes the airways in the lungs to become constricted (narrowed) and paralyzes the cilia, which help the lungs remove irritating particles.

Talk with your doctor if you want to quit smoking, but aren't sure where to start. Many options are available for those who wish to quit smoking but haven't been successful doing so on their own, including stop smoking aids, support groups, and counseling. 

A Word From Verywell

Chronic and acute bronchitis have very similar symptoms, but they are different diseases. Acute bronchitis is reversible and occurs due to an infection. Chronic bronchitis is an irreversible disease that occurs due to recurrent inflammation of the bronchi, usually due to smoking. 

If you have acute bronchitis, you do not need to worry about the long-term health of your lungs. If you have chronic bronchitis, however, you do need to make some lifestyle changes to optimize your breathing and respiratory abilities. Chronic bronchitis is not an uncommon condition, and there are many effective methods of treatment that can help you as you live with the illness. 

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Article Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Heart, Lung, and Blood Institute. Bronchitis.

  2. Cleveland Clinic. Bronchitis. Updated August 12, 2019.

  3. American Lung Association. Acute Bronchitis Symptoms, Causes & Risk Factors. Updated March 13, 2018.

  4. American Lung Association. Chronic Bronchitis.

  5. John Hopkins Medicine. Acute Bronchitis.

  6. John Hopkins Medicine. Bronchitis.

  7. Cleveland Clinic. Bronchitis: Management and Treatment. Updated August 12, 2019.

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