(See also Overview of Idiopathic Interstitial Pneumonias.)
Respiratory bronchiolitis-associated interstitial lung disease and desquamative interstitial pneumonias are types of idiopathic interstitial pneumonia. They have many similarities, so some experts think they may be part of the same disorder. However, desquamative interstitial pneumonia is often more severe. Both disorders primarily affect cigarette smokers in their 30s and 40s. Men are affected more often than women (ratio of almost 2:1).
Some people develop a cough. Most people develop shortness of breath with even minimal exertion.
In people with either disorder, a chest x-ray shows less severe changes than in idiopathic pulmonary fibrosis and may show no changes in up to 20% of people. Chest computed tomography (CT) also shows lung changes. Pulmonary function testing shows a decline in the amount of air contained in the lungs. The amount of oxygen in a blood sample is low.
A lung biopsy is often needed to confirm the diagnosis.
Although doctors cannot always predict how the disorders progress over time, the prognosis for both is good when people stop smoking.
Smoking cessation is the key treatment. Some doctors give corticosteroids or cytotoxic drugs (such as azathioprine or cyclophosphamide) because they may be effective in other interstitial lung diseases, but the effectiveness for these diseases is unknown.