Idiopathic interstitial pneumonias are interstitial lung
diseases that have no known cause and that affect the lungs
similarly. 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 six types of idiopathic
interstitial pneumonias. In decreasing order of frequency, they
are Some experts also consider lymphoid interstitial pneumonia
to be a type of idiopathic interstitial pneumonia. All types
cause shortness of breath and affect the lungs similarly.
However, they differ in how quickly they develop, how they are
treated, and how serious they are. For example, most diseases
take weeks to months to develop, but idiopathic pulmonary
fibrosis takes more than 12 months to fully develop. Acute
interstitial pneumonia takes only 1 to 2 weeks. Chest x-rays,
pulmonary function tests (see Diagnosis of Lung