Smoking-related interstitial lung disease

Cigarette smoking has a clear epidemiological association with lung diseases, characterised by chronic inflammation of both the bronchiolar and the interstitial lung compartments. There are several different smoking-related interstitial lung diseases, mainly desquamative interstitial pneumonia, respiratory bronchiolitis-associated interstitial lung disease and pulmonary Langerhans' cell histiocytosis. The epidemiology of such diseases is largely unknown, although the prevalence of cigarette smoking, particularly in low-income developing countries, indicates that smoking-induced interstitial lung disorders represent a high burden of disease worldwide. The role of chest high-resolution computed tomography has become increasingly important in differential diagnosis and follow-up. A new entity, the syndrome of combined pulmonary fibrosis and emphysema, emerged as another important smoking-related lung disorder with a poor prognosis, associated with the high prevalence of pulmonary hypertension. At the moment the role of anti-inflammatory and immunosuppressive treatment remains unclear, although in clinical practice most of these patients will receive at least one course of corticosteroid therapy. It is vital to stress the importance of identifying these patients and helping them quit smoking.