Popcorn Lung (Bronchiolitis Obliterans)

Popcorn lung, or bronchiolitis obliterans, is a disease that affects the bronchioles, the small airways in the lungs. The disease can be treated but not cured.


The bronchioles of your lungs are inflamed, scarred and damaged you have bronchiolitis obliterans, also called popcorn lung.
Bronchiolitis obliterans (known as popcorn lung) affects the smallest airways of the lungs, the bronchioles.

What is popcorn lung?

Bronchiolitis obliterans, also called popcorn lung, is a respiratory condition that affects the bronchioles of your lungs. The bronchioles are the smallest airways in your lungs. If you have this condition, these airways become inflamed, damaged and then scarred because of inhaling toxic substances or from infections. Other terms for this condition include obliterative bronchiolitis or constrictive bronchiolitis.


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Why is bronchiolitis obliterans called popcorn lung?

The name probably comes from when researchers first identified the disease among workers in a microwave popcorn factory. The workers had breathed in diacetyl, a flavoring chemical used to make the popcorn taste buttery.

Other industries used diacetyl for flavoring. Providers diagnosed workers in those other industries who had breathed in diacetyl with bronchiolitis obliterans. The liquid in electronic cigarettes (e-cigarettes) or vapes also contains diacetyl. There were also cases of the disease found in workers at a coffee roasting plant.

Who is more likely to get popcorn lung?

Certain people have a higher risk of developing bronchiolitis obliterans because they come in close contact with toxic substances in the air. These chemicals are used in some types of manufacturing and can also be found in vapes and e-cigarettes.

Toxic substances associated with developing popcorn lung

  • Acetaldehyde.
  • Ammonia.
  • Chlorine.
  • Diacetyl.
  • Formaldehyde.
  • Fumes from metal oxides.
  • Hydrochloric acid.
  • Mustard gas or sulfur mustard.
  • Nitrogen oxides.
  • Sulfur dioxide.

Medical conditions associated with developing popcorn lung


How common is popcorn lung?

Popcorn lung is a rare disorder, but it can happen to anyone since it can result from an infection or exposure to certain substances.

Bronchiolitis obliterans can also occur without a specific exposure in people who've had a lung transplant. About 50% of people who have lung transplants will developbronchiolitis obliterans syndrome within five years of their transplant procedure. About 10% of recipients of donor marrow also develop bronchiolitis obliterans syndrome within five years.

What is bronchiolitis obliterans syndrome?

This condition, which results in reduced lung function because of the scarring to small airways in the lungs, is the most common type of lung transplant rejection among lung recipients. It can look like an infection at first.

The disease progresses in stages, but not the same way for everyone who has it. One person might stay in an early stage for quite some time, while another goes quickly from one stage to another more advanced stage. A lung function test called spirometry can determine how severe the disease is.


Symptoms and Causes

What are the signs and symptoms of popcorn lung?

Signs and symptoms of popcorn lung include:

Sometimes people who have popcorn lung don’t have symptoms initially.

What causes popcorn lung?

Popcorn lung isn’t contagious. You can’t get it from other people or give it to other people.

Popcorn lung happens from inhaling toxic chemicals, such as diacetyl, formerly used to flavor microwave popcorn. Exposure to these chemicals can happen at work or by vaping. E-cigarettes have many different types of chemicals in them that may be dangerous to your lung tissue. It’s thought that the vapor may affect not only the person vaping but also the people around them.

In people who've had a lung transplant, the disease can occur without exposure to a chemical or infection.

Diagnosis and Tests

How is popcorn lung diagnosed?

Your provider will ask you questions about your medical history and how you’re feeling. Because symptoms like difficulty breathing or being fatigued are common in other conditions, your doctor may recommend certain tests to clarify the diagnosis. These include:

Management and Treatment

How is popcorn lung treated?

The damage from popcorn lung can be severe and reversal isn’t always possible. Management is likely to be more effective if your provider catches the disease early.

The first thing you should do is avoid exposure to the chemicals that cause popcorn lung. If you’re at a job that exposes you to these chemicals, you need to use the recommended protective equipment. If you’re smoking or vaping, you should quit.

Treatments for popcorn lung may include:

  • Corticosteroids to fight inflammation, such as prednisone.
  • Inhalers to help with breathing, such as those with albuterol.
  • Oxygen therapy.
  • Lung transplant, but this is recommended only in the most severe and extreme circumstances.

Complications/side effects of corticosteroids

Corticosteroids work very well to reduce inflammation, but they may cause a host of side effects. These side effects may include:

  • Weight gain.
  • Changes in mood.
  • Nervousness or restlessness.
  • Diabetes or causing existing diabetes to get worse.
  • Trouble sleeping.


How can I reduce my risk of developing popcorn lung?

Start early by taking care of your lungs as best you can. You can do this in the following ways:

  • Avoid using tobacco and e-cigarettes and avoid secondhand smoke and polluted places.
  • Avoid infections when possible. Certain infections can damage your lungs.
  • Follow your healthcare provider's suggestions on maintaining vaccine protection.
  • If you work around dangerous substances, always wear personal protective equipment.

Outlook / Prognosis

What is the outlook for someone with popcorn lung?

There’s no cure for popcorn lung. You’ll need to have life-long care to manage the symptoms, which may not always respond well to treatment.

Living With

How do I take care of myself if I have popcorn lung?

  • Avoid being around air pollution or tobacco smoke.
  • Avoid people who are sick with infections and make sure to practice good hand washing techniques.
  • If you do get sick, get early treatment for infections, even those related to your teeth.
  • Take your medicines as directed.

Make sure that you tell your provider about any gastroesophageal reflux disease symptoms so they can be treated and not cause any additional harm to your lungs.

If you have a chronic illness, you might find it useful to join a support group. Sometimes sharing with others who have similar problems gives you answers and perspectives you might not find elsewhere. The support system may also be useful to caregivers, family and friends.

When should I see my healthcare provider?

Contact your healthcare provider if you have breathing difficulties that aren’t relieved by your rescue inhaler. Call if you have any symptoms that are new or get worse.

Additional Common Questions

What is the difference between bronchiolitis obliterans and bronchiolitis obliterans organizing pneumonia?

Bronchiolitis obliterans and bronchiolitis obliterans organizing pneumonia (BOOP) are two different diseases. Both diseases affect the bronchioles, but the cause of BOOP is infections, drugs or other diseases. The new name of BOOP is cryptogenic organizing pneumonia (COP) if there is no known cause, and most cases of BOOP have no known cause. The most common symptom is a cough that lasts for some time and doesn’t bring up secretions.

Can popcorn lung fix itself?

The short answer to this is no. Bronchiolitis obliterans is irreversible. Once the damage happens, you can’t fix it. You can only try to stop making it worse. Without treatment, it could be fatal.

A note from Cleveland Clinic

Popcorn lung might sound like a made-up disease, but it isn’t. It’s a serious lung condition that requires lifelong management. Follow the recommendations made by your healthcare provider in terms of general health and in terms of dealing with popcorn lung. It’s very important to avoid further exposure to damaging substances.

Medically Reviewed

Last reviewed on 03/16/2022.

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