Hypersensitivity Pneumonitis

Hypersensitivity pneumonitis (HP) is an interstitial lung disease caused by repeated inhalation of certain fungal, bacterial, animal protein or reactive chemical particles, called antigens. While most people who breathe in these antigens don't develop problems, in some people, the body's immune reaction to these particles causes inflammation of the lung. In some cases, parts of the lungs may become scarred.

It's not known why a minority of people exposed to these antigens develop HP. Their genetics and environment may interact to make them more susceptible to the disease.

HP should not be confused with the more common types of allergies, which are caused by small amounts of proteins in the environment such as dust mites, cat dander, pollen and grass. Having seasonal or environmental allergies has nothing to do with having or developing HP.

Our Approach to Hypersensitivity Pneumonitis

Hypersensitivity pneumonitis will often go away if the patient avoids the substance that's triggering the lung inflammation. Some cases of HP persist, however. For these patients, UCSF offers specialized care that includes medication management, treatment for other health problems that often affect people with HP, and a special exercise and education program designed for patients with chronic lung disease. Our specialists review each case as a team to ensure that every patient gets the right diagnosis and most effective care.

For patients who get worse despite treatment, lung transplantation may be an option. UCSF is home to a high-performing lung transplant program with the expertise to handle the most complex, challenging cases.