Idiopathic pulmonary fibrosis (IPF), formerly known as cryptogenic fibrosing alveolitis, is a rare, progressive illness of the respiratory system, characterized by the thickening and stiffening of lung tissue, that surrounds the air sacs, and is associated with the formation of scar tissue. It is a type of chronic pulmonary fibrosis characterized by a progressive and irreversible decline in lung function.
Symptoms typically include gradual onset of shortness of breath and a dry cough. Other changes may include feeling tired, and clubbing abnormally large and dome shaped finger and toenails. Complications may include pulmonary hypertension, heart failure, pneumonia or pulmonary embolism.