Bronchiolitis obliterans with organizing pneumonia (BOOP)

Bronchiolitis obliterans with organizing pneumonia (BOOP) is a rare lung condition in which the small airways (bronchioles), the tiny air-exchange sacs (alveoli) and the walls of small bronchi become inflamed and plugged with connective tissue. BOOP can have many causes.

In some people, BOOP causes no signs or symptoms. Most people who have BOOP experience a persistent nonproductive cough and — depending on how much of the lung is affected — shortness of breath with exertion.

Some forms of BOOP have identifiable causes, such as:

• Infections. BOOP sometimes occurs after people have had certain infections, including chlamydia, influenza or malaria.
• Inflammatory disorders. The risk of BOOP appears to be heightened for people who have disorders such as lupus, rheumatoid arthritis or scleroderma.
• Cancer treatment. People who have received certain types of chemotherapy or radiation to their chests sometimes develop BOOP.
• Transplanted tissue. Bone marrow, lung, kidney and stem cell transplants sometimes trigger bronchiolitis obliterans with organizing pneumonia.
• Drug exposure. Drugs that have been linked to BOOP include cocaine, gold salts, and some antibiotics and anti-seizure medications.

Some think that gastroesophageal reflux disease can be a provoking factor.

If your doctor is unable to identify a cause, the disorder is called cryptogenic organizing pneumonia.

Most people recover after weeks or months of treatment with a steroid such as prednisone, or treatment of the underlying infection if that's the cause. But in some people, BOOP can progress in spite of treatment.