Tobacco smoke-related diffuse lung diseases.

Cigarette smoking has been associated with several diffuse lung diseases in which both bronchiolar and interstitial lung inflammation appear to result from chronic tobacco smoke inhalation. These diseases occur primarily in relatively young adult smokers and include desquamative interstitial pneumonia, respiratory bronchiolitis-associated interstitial lung disease, and pulmonary Langerhans cell histiocytosis. Although these diseases are associated with characteristic histopathologic and radiological features, there is significant overlap among these diseases, and some smokers may exhibit features indicative of the broad spectrum of smoking-related interstitial and bronchiolar lung injury patterns. Cigarette smoking has also been associated with acute eosinophilic pneumonia, and it increases the risk of developing other fibrotic interstitial lung diseases such as idiopathic pulmonary fibrosis and rheumatoid arthritis-associated interstitial lung disease. Although relatively uncommon, these smoking-related diffuse lung diseases should be recognized by clinicians as an important subset in the spectrum of interstitial lung diseases in which smoking cessation forms a central part of disease management. With the exception of acute eosinophilic pneumonia, which responds well to corticosteroid therapy, the role of corticosteroid and other immune-suppressive treatments in the management of smoking-related interstitial lung diseases is not entirely clear and is probably of limited utility, particularly in the absence of smoking cessation.