Smoking-related interstitial lung disease.

BACKGROUND: Smoking-related interstitial lung diseases (SR-ILDs) are a heterogeneous group of diseases with major clinical significance. Reliable epidemiological data are not yet available.

METHOD: Review of pertinent literature retrieved by a selective search in PubMed.

RESULTS: The available data on many aspects of SR-ILDs are sparse, but recent studies on the pathophysiology and targeted treatment of these conditions have revealed ways in which clinical outcomes can be improved. Highresolution computerized tomography should be used for differential diagnosis; lung biopsy is often unnecessary. Oncogenic mutations play a role in the pathogenesis of pulmonary Langerhans-cell histiocytosis (PLCH). In the future, cladribine and vemurafenib may be treatment options for PLCH. Desquamative interstitial pneumonia (DIP) may be difficult to distinguish from respiratorybronchiolitis-associated interstitial lung disease (RB-ILD); DIP is treated with steroids and sometimes with immune suppressants. In idiopathic pulmonary fibrosis (IPF), the antifibrotic drugs pirfenidone and nintedanib can delay disease progression. Smoking is also a risk factor for combined pulmonary fibrosis and emphysema (CPFE), rheumatoid-arthritis-associated interstitial lung disease (RA-ILD), pulmonary alveolar proteinosis (PAP), acute eosinophilic pneumonia (AEP), and diffuse alveolar hemorrhage (DAH) in Goodpasture syndrome.

CONCLUSION: In smokers with exertional dyspnea and/or a nonproductive cough, SR-ILDs must be considered in the differential diagnosis. If an SR-ILD is suspected, the patient should be referred to a pulmonary specialist. Early treatment and smoking cessation can improve clinical outcomes, particularly in the acute and chronically progressive types of SR-ILD.