Hypersensitivity pneumonitis is a type of interstitial lung disease (ILD) caused by repeatedly breathing in certain irritants, such as molds, bacteria, animal proteins and other reactive chemicals.
Pneumonitis is a general term used by health professionals to refer to noninfectious reasons for lung inflammation. Since this inflammation can lead to difficulty breathing, it’s important to identify the cause and eliminate exposure to it. And although hypersensitivity pneumonitis is treatable, it can leave permanent damage and scarring in the lungs if not caught early.
That’s why it’s important to work with a team of interstitial lung disease specialists, like those at The Ohio State University Wexner Medical Center, to diagnose and treat your hypersensitivity pneumonitis.
Our pulmonary experts have years of experience helping people with these lung conditions. We’ll provide you with comprehensive and personalized care.
What is pneumonitis vs. pneumonia?
Pneumonitis is a general term for inflammation of the lungs. Technically, pneumonia is a type of pneumonitis, but inflammation in pneumonia is caused by an infection by bacteria or other germs.
Pneumonitis is caused by an allergic reaction to some type of irritant, whether airborne (hypersensitivity pneumonitis) or a medication (drug-induced pneumonitis).
Also, pneumonia only affects a small portion of the lungs and noninfectious pneumonitis is usually spread throughout the lungs. This can be an important distinction when trying to differentiate between these conditions.
Hypersensitivity pneumonia causes
Hypersensitivity pneumonitis happens when the substances you inhale irritate the small air sacs in your lungs. Then, your immune system reacts by causing inflammation, which can make it harder to breathe and get oxygen to your blood.
There are a variety of irritants, or antigens, that are known to cause this reaction. They include:
- Mold
- Fungi
- Bacteria
- Animal proteins
- Chemicals
These particles are sometimes found in these items:
- Bird feathers and droppings
- Animal furs
- Contaminated foods
- Humidifiers or hot tubs
- Wood
- Dust
Approximately 40-50% of the time, the specific environmental irritant cannot be identified.
Hypersensitivity pneumonitis symptoms
Symptoms of this condition can resemble those of other respiratory illnesses, so it’s important to see your doctor to help you determine the cause.
Signs of hypersensitivity pneumonitis can be acute (short-term) or chronic (long-term) depending on how long you’re exposed to the chemicals responsible for your symptoms.
Acute symptoms include:
- Fever
- Chills
- Achiness
- Headache
If pneumonitis goes undetected or untreated, you might experience scarring (fibrosis) of the lungs and develop chronic pneumonitis.
Chronic symptoms include:
- Shortness of breath
- Dry cough
- Exhaustion
- Loss of appetite and weight loss
Diagnosing hypersensitivity pneumonitis
Identifying hypersensitivity pneumonitis can be difficult since symptoms often mimic other respiratory illnesses.
However, in the absence of other causes, such as infection or other underlying condition, we can explore pneumonitis and determine if you’ve been exposed over time to one or more of the substances known to bring about these symptoms.
We’ll also use a variety of other medical tests to help us narrow down the possible causes of your lung issues. Those tests include:
- Blood tests
- Bronchoscopy
- Lung function tests, like spirometry and oximetry
- Chest X-rays and CT scans
- Lung biopsy
- Home evaluation to look for molds or other antigens
Imaging tests (X-rays and CT scans) are especially important when diagnosing pneumonitis, because it appears in the lungs differently than pneumonia. Noninfectious pneumonitis spreads throughout the lungs and pneumonia typically affects only a small portion.
Hypersensitivity pneumonia treatment
If we can determine what inhalant is responsible for your symptoms and eliminate it, inflammation in most cases of hypersensitivity pneumonitis is reversible.
For more serious cases, some symptoms may persist even after we remove the irritant from your environment. Then, we might recommend some medications (corticosteroids, for example) to help with inflammation.
We also might recommend pulmonary rehabilitation to help you regain strength in your lungs and learn to breathe more efficiently.
Here at the Ohio State Wexner Medical Center, we have an interstitial lung disease program with staff dedicated to caring for and treating people with these types of pulmonary conditions. Our collaborative approach and expertise will allow you to get back on your feet, enjoying life.