Interstitial lung disease (ILD) is a general term for a number of diseases characterised by progressive pulmonary fibrosis or “scarring” of the lungs. The term fibrosis implies formation of abnormal connective tissue within the lung parenchyma. These diseases are less commonly seen than airways diseases such as asthma and chronic obstructive pulmonary disease (COPD). However like COPD, they produce progressive debilitating breathlessness for the patient.