Pulmonary fibrosis is a lung disease that occurs when lung tissue becomes damaged and scarred. This thickened, stiff tissue makes it more difficult for your lungs to work properly. Pulmonary fibrosis is a condition in which the lungs become scarred over time. Symptoms include shortness of breath, a dry cough, feeling tired, weight loss, and nail clubbing. Complications may include pulmonary hypertension, respiratory failure, pneumothorax, and lung cancer. Pulmonary fibrosis can be caused by many conditions including Chronic inflammatory processes like sarcoidosis, Wegener's granulomatosis Infections. Environmental agents like asbestos, silica, exposure to certain gases. It is a lung disease that occurs when lung tissue becomes damaged and scarred. This thickened, stiff tissue makes it more difficult for your lungs to work properly.  The scarring associated with pulmonary fibrosis can be caused by a multitude of factors.