Merck Manual

Please confirm that you are not located inside the Russian Federation

honeypot link

Overview of Idiopathic Interstitial Pneumonias


Joyce Lee

, MD, MAS, University of Colorado School of Medicine

Last full review/revision Jun 2021| Content last modified Jun 2021
Click here for the Professional Version
Topic Resources

Idiopathic interstitial pneumonias are interstitial lung diseases that have no known cause that have some similarities in symptoms and how they affect the lungs.

  • Some types of these diseases are much more serious than others.

  • Diagnosis requires chest x-rays, computed tomography, and usually analysis of a sample of lung tissue (biopsy).

  • Treatment depends on the disease type.

The word idiopathic means of unknown cause, so when the cause of interstitial lung disease is not identified, idiopathic interstitial pneumonia is diagnosed. Pneumonias are often thought of as infections, but these diseases do not appear to result from infection.

There are eight types of idiopathic interstitial pneumonias. In decreasing order of frequency, they are

All types cause cough and shortness of breath and affect the lungs similarly. The ends of the fingers may become thick or club-shaped (see figure Recognizing Finger Clubbing Recognizing Finger Clubbing Clubbing is enlargement of the tips of the fingers or toes and a change in the angle where the nails emerge. Clubbing occurs when the amount of soft tissue beneath the nail beds increases. It... read more Recognizing Finger Clubbing ). Through a stethoscope, doctors often hear crackling sounds. Although symptoms may be similar, disorders differ in how quickly symptoms develop, how they are treated, and how serious they are.


Diagnosis of Idiopathic Interstitial Pneumonias

  • Chest computed tomography

Computed tomography (CT) of the chest is the main imaging tool used in the evaluation of idiopathic interstitial pneumonias. CT may allow doctors to make a diagnosis. If not, doctors remove a small sample of lung tissue for examination under a microscope (lung biopsy). Usually, biopsy is done surgically with use of a thoracoscope Thoracoscopy Thoracoscopy is the visual examination of the lung surfaces and pleural space through a viewing tube (a thoracoscope). Thoracoscopy is used to view the lung and the space surrounding the lungs... read more .

Treatment of Idiopathic Interstitial Pneumonias

  • Smoking cessation

  • Often drugs, corticosteroids or novel antifibrotic drugs, depending on the disease

  • Sometimes lung transplantation

Other treatments depend on the type of idiopathic interstitial pneumonia but may include corticosteroids or other drugs, such as novel antifibrotic drugs.

Drugs Mentioned In This Article

Generic Name Select Brand Names
NOTE: This is the Consumer Version. DOCTORS: Click here for the Professional Version
Click here for the Professional Version
Others also read
Test your knowledge
Mesothelioma is cancer of the membrane that surrounds the chest wall (pleura) or abdomen. In the United States, which of the following is the only known cause of mesothelioma? 
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID

Also of Interest

Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID
Download the Manuals App iOS ANDROID