Key Facts:
- Bronchiolitis obliterans is a rare chronic lung disease that worsens over time.
- This disease was first discovered in workers at a microwave popcorn plant who had inhaled the flavoring chemical diacetyl. That is how bronchiolitis obliterans became known as ‘popcorn lung’.
- Exposure to other chemicals, some lung infections, autoimmune diseases and complications from lung transplants can also cause bronchiolitis obliterans.
- It is important to note that the similarly named bronchiolitis obliterans organizing pneumonia (BOOP), now referred to as Cryptogenic Organizing Pneumonia (COP), is a completely different disease.
How it Affects Your Body
The very small airways of the lungs are called bronchioles. Bronchioles can become injured as a result of inhaling a harmful substance, due to an infection, from an autoimmune response or as a complication to a lung transplant. Most of the time, the injury heals normally. Occasionally the body’s repair process becomes overactive, causing the build-up of scar tissue. The thick scar tissue blocks the bronchioles and prevents air from passing through to the alveoli, also called air sacs. This makes it harder for the body to absorb oxygen. The scarring and narrowing of the bronchioles may continue to worsen over time. If left untreated, it could result in irreversible lung damage and respiratory failure.
What Causes Bronchiolitis Obliterans
Bronchiolitis obliterans is most commonly caused by breathing in toxicants over time. Diacetyl is a frequent cause of exposure that and can be found in artificial butter flavoring and odor products such as popcorn, cake mixes and candy. It also is found in tobacco smoke, flavored tobacco products and vaping products. Some other toxicants linked to causing bronchiolitis obliterans are:
- Acetaldehyde, found in cannabis and e-cigarette smoke
- Formaldehyde, a highly irritating chemical used in adhesives and building materials and emitted from e-cigarette smoke
- Metal oxide fumes, a byproduct of welding
- Sulfur dioxide, released by burning fossil fuels
- Ammonia
- Chlorine
- Nitrogen oxides
- Hydrochloric acid
- Mustard gas, or sulfur mustard
Besides environmental exposure, bronchiolitis obliterans can be caused by severe respiratory infections, such as RSV, and some forms of pneumonia or bronchitis. If you have been diagnosed with an autoimmune disease, such as rheumatoid arthritis, you are also at a higher risk of developing bronchiolitis obliterans. If you have had a lung transplant, you are at risk of developing the condition if your body rejects the new organ. About 50% of recipients of a lung transplant develop the condition within five years. This is called bronchiolitis obliterans syndrome. Some people who have a bone marrow transplant from a donor may also develop this condition. This occurs in about 10% of people receiving a bone marrow transplant and typically develops within five years of their transplant.
