Popcorn lung: What is it, and who is at risk?

Popcorn lung is a rare condition that results from damage to tiny air sacs and passages in the lungs. Symptoms include breathing problems such as shortness of breath, coughing, and wheezing. Experts say it's possible that using e-cigarettes and vaping can cause popcorn lung.

What is popcorn lung?

Popcorn lung (medical name: bronchiolitis obliterans) is a rare condition in which lung damage starts in the small airways in the lungs, called bronchioles. It can be caused by inhaled chemicals, lung infection, autoimmune disease, or rejection of a transplanted lung. Although the bronchioles may heal normally, sometimes the inflammation and subsequent healing process cause scar tissue to build up.

Thick scar tissue can block the bronchioles and keep air from passing through to the body. Over time, the condition can result in respiratory failure.

Popcorn lung was first discovered in workers at a microwave popcorn plant. They had breathing problems that were found to be caused by inhaling a butter-flavored chemical called diacetyl. Many other chemicals, including chlorine and formaldehyde, can also cause this condition.

Who is at risk for popcorn lung?

Those at risk for developing popcorn lung include people who

• have been inhaling the chemical diacetyl or other harmful chemicals
• have had a lung transplant
• have a severe respiratory infection
• have an autoimmune disease such as rheumatoid arthritis.

Diacetyl is no longer used in popcorn manufacturing due to the risk of harm to workers. However, it is still used in other industries.

Diacetyl is also added to the liquid used in some flavored e-cigarettes. Vaping involves heating a liquid and inhaling the aerosol into the lungs.

Is there a link between popcorn lung and vaping?

Studies of the health effects of e-cigarettes are ongoing. An article published in Current Opinion in Immunology suggests a link between popcorn lung and vaping. The article notes that diacetyl is a proven cause of popcorn lung, and that diacetyl is a flavoring used in some e-cigarettes.

In addition, thousands of cases of e-cigarette- or vaping-use-associated lung injury (EVALI) were reported in 2019 and 2020. This potentially fatal condition includes bronchiolitis, the inflammatory lung disease that occurs in popcorn lung. While cases of EVALI have dropped since 2020 (likely due to the discovery — and subsequent removal — of a form of vitamin E in vaping liquid that may trigger the condition), they have not disappeared entirely.

The American Lung Association has called popcorn lung "a dangerous risk of flavored e-cigarettes."

E-cigarettes have other health risks, too. In addition to diacetyl, they can contain other harmful chemicals and ultrafine particles that can be inhaled deep into the lungs. Experts continue to study the ways in which vaping can damage lungs.

The U.S. Surgeon General maintains a website entitled "Know the Risks" to address the use of e-cigarettes, especially among young people. The site strongly recommends that young people do not begin vaping and if they do, to quit.

Popcorn lung symptoms

Symptoms of popcorn lung include:

• shortness of breath
• wheezing
• coughing not caused by a cold or asthma.

Symptoms get worse over time and can flare up during exercise or exertion.

How is popcorn lung diagnosed?

Symptoms of popcorn lung can be similar to symptoms of other lung conditions. To diagnose popcorn lung, a doctor will:

• ask about your health history, including if you use e-cigarettes to vape
• listen to your breathing with a stethoscope
• order tests such as a chest x-ray or CT scan
• request pulmonary function testing (PFT), a noninvasive test to see how much air you can breathe in and breathe out.

In some cases, it may be necessary to do a lung biopsy, in which a small piece of lung tissue is removed for study.

How is popcorn lung treated?

Popcorn lung can't be cured, but treatments are available to slow its progression and ease symptoms.

Treatments include:

• corticosteroids such as prednisone, to reduce inflammation
• using an inhaled medicine such as albuterol, which helps to open up your bronchial tubes
• supplemental oxygen to raise blood oxygen levels
• antibiotics.

In very rare cases when the lung damage is life-threatening, a lung transplant may be needed.

It is important that popcorn lung be diagnosed and treated as soon as possible. Early treatment is more likely to keep the disease from getting worse.

If popcorn lung was caused by breathing in a harmful chemical, it is crucial to reduce your exposure to that chemical and any other harmful chemicals.