Merck Manual

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Comparing Types of Idiopathic Interstitial Pneumonias*

Comparing Types of Idiopathic Interstitial Pneumonias*


People Most Often Affected

Percentage of Affected People Who Smoke Cigarettes



Idiopathic pulmonary fibrosis

More frequently, men over 50

More than 60%

Pulmonary rehabilitation

Lung transplantation

Pirfenidone or nintedanib

50–70% die in 5 years.

Desquamative interstitial pneumonia

More frequently, men aged 30–50

More than 90%

Smoking cessation


70% survival at 10 years.

Nonspecific interstitial pneumonia

More frequently, women aged 40–60

Fewer than 40%


Fewer than 50% die in 5 years.

Mortality rate: widely variable, but generally better than idiopathic pulmonary fibrosis.

Cryptogenic organizing pneumonia

People of any age, usually aged 40–50

Fewer than 50%


Relapses are common

5-year survival rate is > 90%

Death is rare.

Respiratory bronchiolitis–associated interstitial lung disease

People aged 30–50 (slightly more men)

More than 90%

Smoking cessation


Death is rare as long as people stop smoking.

Acute interstitial pneumonia

People of any age


Best treatment unknown

Sometimes corticosteroids

More than 50% die in less than 6 months.

Lymphoid interstitial pneumonia

Mostly women of any age



The prognosis is difficult to predict,

Idiopathic pleuroparenchymal fibroelastosis

People of any age (median age 57)

Usually non-smokers

Best treatment unknown (possibly corticosteroids)

5-year survival rate is approximately 25 to 60%.

* In decreasing order of frequency.