[Interstitial lung diseases].
Interstitial lung diseases (ILD) are an heterogeneous group of inflammatory diseases characterized by an anatomical distortion of peripheral airways and interstitium, determined by a first stage of alveolitis and a following stage of fibrosis. Natural history of several ILD is characterized by slow and progressive destruction of alveolar-capillary functional units, often with respiratory failure and death. For their smoldering evolution and not specificity of symptoms (exertional dyspnea and cough) ILD may remain not diagnosed and not treated for a long time.