Respiratory bronchiolitis-associated interstitial lung disease and desquamative interstitial pneumonia are rare conditions that cause chronic lung inflammation and occur mostly in current or former cigarette smokers.
These conditions are types of idiopathic interstitial pneumonia (see Overview of Idiopathic Interstitial Pneumonias). They have many similarities, so that 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, with most people developing shortness of breath with even minimal exertion. Men are affected more often than women (ratio of almost 2:1).
A chest x-ray shows less severe changes than in idiopathic pulmonary fibrosis and may show no changes in up to 20% of people. Computed tomography (CT) also shows lung changes. Pulmonary function tests (see Pulmonary Function Testing (PFT)) show 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.
About 70% of people who have respiratory bronchiolitis-associated interstitial lung disease or desquamative interstitial pneumonia survive for 10 years or longer. The response is even better 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 is unknown.
Last full review/revision October 2013 by Harold R. Collard, MD