Popcorn Lung (Bronchiolitis Obliterans) Symptoms, Causes, Life Expectancy

  • Medical Author:
    Charles Patrick Davis, MD, PhD

    Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

  • Medical Author: George Schiffman, MD, FCCP
    George Schiffman, MD, FCCP

    Dr. Schiffman received his B.S. degree with High Honors in biology from Hobart College in 1976. He then moved to Chicago where he studied biochemistry at the University of Illinois, Chicago Circle. He attended Rush Medical College where he received his M.D. degree in 1982 and was elected to the Alpha Omega Alpha Medical Honor Society. He completed his Internal Medicine internship and residency at the University of California, Irvine.

  • Medical Editor: Melissa Conrad Stöppler, MD
    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD

    Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

What is popcorn lung (bronchiolitis obliterans)?

Popcorn lung is a serious and irreversible condition in which the tiny air sacs in the lungs become scarred and constricted, which results in no air movement or O2 - CO2 exchange in the lungs.

Other names for popcorn lung are bronchiolitis obliterans and obliterative bronchiolitis.

What causes popcorn lung?

In 2004, The US Centers for Disease Control and Prevention (CDC) reported several cases of bronchiolitis obliterans in workers in a microwave popcorn plant in Missouri in 2000. After investigation by the NIOSH (National Institute of Occupation Safety and Health), it was discovered that a flavoring agent termed diacetyl (2,3-butanedione) was used to give the popcorn a buttery taste. Inhaling this chemical flavoring likely contributed to the development of this lung disease.

Popcorn lung (bronchiolitis obliterans) often is associated with symptoms of cough and shortness of breath, similar to that seen in people with chronic obstructive pulmonary disease (COPD). This process is irreversible with currently available therapy.

More recently, a legal case was settled in Colorado for over 7 million dollars. The award was granted to a consumer who developed bronchiolitis obliterans ("popcorn lung") after eating two bags of microwaved popcorn every day for 10 years. Since workers who manufacture microwaved popcorn were at risk, the judgment stated that the popcorn manufacturers and the supermarket corporations should have realized that consumers could also be at risk of this lung disease.

Another chemical similar to diacetyl called 2,3-pentanedione also is suspected as a cause of the disease. Both diacetyl and 2,3-pentanedione are released into the air during grinding and packaging of coffee beans. These two chemicals are members of the chemical class alpha-diketones. Other members of this chemical class may cause similar lung damage according to the CDC, but they have not yet been studied.

Other causes of popcorn lung may be due to some of the following chemicals when inhaled.

  • Acetaldehyde
  • Formaldehyde
  • Sulfur dioxide
  • Nitrogen oxides
  • Chlorine
  • Hydrochloric acid
  • Ammonia
  • Metal oxides (formed during welding)
  • Mustard gas (chemical weapon)

Can e-cigarettes cause popcorn lung?

A study published in 2015 in the Journal Environmental Health Perspectives showed that harmful chemicals associated with "popcorn lung" are present in many types of flavored e-cigarettes, particularly those with flavors like fruit and candy that may appeal to young smokers. Of the 51 flavored e-cigarettes tested, flavoring chemicals were found in 47 and diacetyl specifically in 39 samples. This suggests a potentially dangerous level of exposure via e-cigarettes to chemicals that can cause severe lung damage.

What are the symptoms of popcorn lung?

The symptoms of "popcorn lung" are primarily cough and shortness of breath. These symptoms can develop slowly and subtly, gradually progressing to more disabling symptoms over time. Other symptoms of popcorn lung include:

Severe exposure of these chemicals as seen in people who work at microwave popcorn plants may include inflammation of the skin and mucosal surfaces (eyes, nose, and/or throat). In general, however, because the symptoms are so similar to tobacco-related chronic obstructive pulmonary disease (COPD) as well as asthma, the diagnosis may be difficult to make without a high level of suspicion.

How is popcorn lung diagnosed?

The diagnosis of bronchiolitis obliterans lung begins by taking a thorough history, and additional testing is required to confirm the diagnosis. Lung function testing (spirometry), chest X-rays, and CT scans usually are done to help determine a preliminary diagnosis. Lung tissue biopsy, which often requires an open lung surgical procedure, is necessary to confirm the diagnosis of bronchiolitis obliterans. The disease can be randomly located in lung tissue, making it difficult at times for the pathologist to make an accurate diagnosis.

What is the treatment for popcorn lung?

The primary treatment of popcorn lung is removal of any exposure to the diacetyl agent. Special facial coverings and a respirator masks are required for workers exposed to this chemical. In some cases, the person must be removed from diacetyl exposure and the environment.

For consumers, avoiding exposure to diacetyl is essential. In some people, this will result in a gradual decrease in symptoms if the process was diagnosed early enough. Steroids, antibiotics, and oxygen may be used to treat symptoms. In others, however, the disease can progress and may even require lung transplantation.

What is the life expectancy for popcorn lung? Is it fatal?

According to the CDC, most individuals show little or no response to medical treatments for popcorn lung. However, if a person is diagnosed early and exposure to the chemicals are stopped, he or she may note a decrease or discontinuation of symptoms such chronic cough.


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Medically Reviewed on 11/28/2017

CDC. "Flavorings-related lung disease (Coffee Processing Facilities)." Updated: Feb 09, 2017.

CDC. "Flavorings-related lung disease." Updated: Dec 19, 2016.