Diffuse interstitial lung disease often presents with progressively worsening dyspnea as its most prominent symptom. Exacerbation after activity, increased respiratory rate and heart rate may appear early in the disease. Most patients also have a dry cough of varying degrees, often irritating, with short-term exacerbations, which can be triggered by exertion and deep inspiration, and sometimes a small amount of white mucus sputum, which increases in volume and turns yellow if secondary infection is present. Some patients have chest pain, night sweats, loss of appetite, weight loss, emaciation, weakness, etc., and are prone to recurrent spontaneous pneumothorax. The vast majority of the disease continues to progress and eventually dies of respiratory failure. In case of secondary pulmonary interstitial fibrosis, there are also some extra-pulmonary manifestations, such as Raynaud’s phenomenon, etc.