Diagnosing and Treating Hypersensitivity Pneumonitis | American Lung Association

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Diagnosing and Treating Hypersensitivity Pneumonitis

You should schedule an appointment with your doctor who will check if you have hypersensitivity pneumonitis. It is diagnosed by a detailed history, including possible exposure to certain dusts.  Your doctor will ask you about such exposures, perform a physical examination and may order some or all of the tests described in the section below.

What to Expect

Your doctor will do a physical exam and listen to your lungs with a stethoscope. Individuals with hypersensitivity pneumonitis may have abnormal lung sounds or crackles. Your doctor may also use a small instrument called a pulse oximeter that is placed on the finger to check the oxygen levels in your blood.

Your doctor will ask if you have exposure to any kind of dust at home or at work. Some specific questions that your doctor may ask are as follows:

  • Have you been exposed to any water damage in your house or at work, especially from humidifiers, heating systems, or air conditioners?
  • Do you have a hot tub at home?
  • Have you have been exposed to bird droppings/ do you have any birds as pets/ do you have any feather cushions or down pillows?

You can bring in a family member to the doctor’s visit since they may remember exposure to certain dusts that you may have forgotten or overlooked. Rarely, if no obvious cause for exposure is determined, an industrial hygienist who is trained to detect such dust exposure may have to visit your home or workplace.

How Hypersensitivity Pneumonitis Is Diagnosed

Your doctor may order any of the following tests to assist in the diagnosis process.

Chest x-ray and CT (computerized tomography) scan which may be able to show early stages of the disease and if there is any scarring.
Lung function tests show how well you breathe to see if your lungs are working correctly.
Blood tests are done to find out if you have developed antibodies against the dust (allergen). These blood tests can help show if you have been exposed to a certain dust.
Bronchoscopy is when a bronchoscope (small flexible tube about the size of a pencil with a video camera attached at its end) is passed either through your nose or mouth. The scope is then passed into your vocal cords, windpipe and the air passages. This tool can be used to collect specimens from your lung for further testing.  
Video-assisted thoracic surgery (VATS) or open lung biopsy is performed by a cardiothoracic surgeon under general anesthesia. It is another way to get lung tissue for further testing.

How Hypersensitivity Pneumonitis Is Treated

The single most important thing that you can do is avoid the dust that causes the disease. If you do so, your lungs can return to normal function, as the disease is completely reversible in the early stages. Completely avoiding the dust is sometimes not possible, unless you remove yourself from the dust-causing environment. Your doctor may recommend completely avoiding the dust by relocating to a new home or job. If you have bird fancier's lung, then it is possible you may have to give up your pet bird.

In patients who have severe cases, treatment may include prescription steroids, such as prednisone. You may be required to take this medication for up 3 months and sometimes longer. Steroids may help with your symptoms; however, it will not cure the disease. Steroids can also cause certain side effects such as weight gain, thinning of the bones, cataracts, abnormal blood sugar levels and increased pressure in your eyes.


    This content was developed in partnership with the CHEST Foundation, the philanthropic arm of the American College of Chest Physicians.


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