Causes and Risk Factors of Acute Bronchitis

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Acute bronchitis is usually caused by a virus or bacteria. Sometimes exposure to environmental irritants may also cause this condition.

This article details the typical causes of acute bronchitis and the factors that can put you at risk.

Woman who is sick

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Common Causes 

Although the most common cause of acute bronchitis is a virus, it is also possible for bacteria to cause this condition. Usually, acute bronchitis happens after you have:

The virus or bacteria may travel from the nose or throat to the bronchi. Then the infection causes inflammation in the bronchi that makes them swell. As a result, you start coughing and make mucus as your body tries to eliminate the infection. The swelling also affects the ability of air to pass through the bronchi, so you may have wheezing or shortness of breath.

It is also possible to develop this condition after breathing in substances that irritate your lungs, such as chemical compounds. 

Environmental causes may include: 

  • Tobacco smoke
  • Air pollution
  • Dust
  • Vapors
  • Strong fumes
  • Allergens
  • Chemical cleaning products 


Although acute bronchitis is not a genetic condition, genetics may be a factor in developing the illness.

You may have a higher risk of getting acute bronchitis or respiratory infections based on specific genetic variations, but researchers have not determined the exact genes that are responsible.

Scientists have discovered that children with some genetic variants are more likely to develop bronchitis because they are more sensitive to secondhand tobacco smoke and chemical compounds in the air. It is possible that a combination of factors—such as air pollution and genetics—plays a role in having this condition.

Cardiovascular and Other Health Risk Factors 

Having a cardiovascular disease does not cause acute bronchitis. However, cardiovascular and lung conditions can make the symptoms of acute bronchitis worse. For example, shortness of breath or wheezing may be worse.

You are more vulnerable to getting acute bronchitis if you have: 

  • Allergies 
  • Chronic sinusitis 
  • Enlarged tonsils or adenoids

Lifestyle Risk Factors 

There are certain lifestyle risk factors that increase the risk of having acute bronchitis. If you have the following factors, talk to your healthcare provider. 


Exposure to secondhand tobacco smoke or smoking yourself is one of the most common lifestyle risk factors. Using products such as cigarettes or cigars can damage your lungs and make it more likely that you will have bronchitis. 

If you do get acute bronchitis, it can last longer and cause more severe symptoms because you smoke. For example, you may have more trouble breathing or produce more mucus in the lungs. Ask your healthcare provider for help if you have problems quitting smoking on your own. 

Chemical Products 

If you are exposed to chemical products that can be inhaled, then you may be at a higher risk of getting acute bronchitis.

Exposure can happen at work, school, or in other areas.

Protect Yourself

If you are around chemical products or fumes, make sure to wear protective gear and limit how much time you spend in the setting.

Air Pollution 

Air pollution is considered a lifestyle risk factor for bronchitis. You are more likely to be exposed to air pollution in urban environments with more cars and factories. However, anyone can come in contact with air pollutants that irritate the bronchi. 

Exposure to Infections 

If you work or live in a setting that creates a high risk of coming into contact with viruses or bacteria, this increases your chance of developing acute bronchitis. Work settings such as hospitals are one example.

You may be able to reduce your risk by following hygiene best practices, such as:

  • Washing your hands or using hand sanitizer 
  • Wearing a mask or protective gear
  • Not touching your face
  • Avoiding people who are sick if possible 

A Word From Verywell

If you are not feeling better two to three weeks after your first symptoms of acute bronchitis develop, then you should talk to a healthcare provider. They can determine the cause of your illness and recommend more treatment. Finding the cause can eliminate confusion and ease your concerns.  

If you have heart or lung disease, it is important to monitor your symptoms and get help right away if you develop problems breathing. Sometimes the symptoms of acute bronchitis can be similar to other health conditions, so you should not wait to get help. People with heart or lung disease are more likely to have complications, such as pneumonia

4 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. MedlinePlus. Acute bronchitis.

  2. Johns Hopkins Medicine. Acute bronchitis.

  3. Ghosh R, Topinka J, Joad JP, Dostal M, Sram RJ, Hertz-Picciotto I. Air pollutants, genes and early childhood acute bronchitis. Mutat Res. 2013;749(1-2):80-86. doi:10.1016/j.mrfmmm.2013.04.001

  4. Ohio State University. Acute bronchitis.

By Lana Bandoim
Lana Bandoim is a science writer and editor with more than a decade of experience covering complex health topics.