A progressive disease, pulmonary fibrosis is characterized by scarring and thickening of lung tissues. This damage occurs as a result of repeated injury to the lungs. Common symptoms are shortness of breath and a dry, hacking cough that does not improve. Other symptoms that a person may develop over time include aching muscles, enlargement of the fingers or toes, and respiratory failure. While there is no cure, treatments are available to slow down the progression of pulmonary fibrosis.