Causes of Lung Scarring

Scarring of the lungs, also called pulmonary fibrosis, interstitial lung disease, fibrosing alveolitis, interstitial pneumonitis and Hamman-Rich syndrome, is a chronic disease that involves swelling and scarring of the air sacs and tissue between cells (interstitial tissue) of the lungs. This scarring can make your lungs stiff and leads to difficulty breathing. There are several causes of lung scarring and the severity can range from mild to potentially fatal.

Jobs that involve working with asbestos, metal, dust or ground stone can cause pulmonary fibrosis. When the particles emitted into the air by these materials are inhaled they can damage the alveoli, the air sacs inside the lungs where the exchange of oxygen and carbon dioxide takes place. This can cause scarring.

Asbestosis, caused by exposure to asbestos, causes scarring and might lead to lung cancer. Silicosis, caused by the inhalation of silica dust, will also cause scarring in the lungs. Mining of gold, lead, copper, zinc, iron and anthracite can result in silicosis if the proper precautions are not taken. Workers in foundries are also at risk for scarring on the lungs caused by silicosis. Sandstone grinding, sandblasting, tunneling, granite carving, concrete breaking and the manufacture of china exposes workers to silica. Tiny particles are transported to the aveoli, where they cause scarring. The severity of silicosis depends on the concentration in the air and the length of exposure.

People exposed to some types of chemical fumes, like ammonia or chlorine gases, may experience pulmonary fibrosis. Long-term exposure to other environmental substances can damage the lungs as well. Grain, sugar cane, and dust from animal droppings can scar your lungs. Moldy hay can cause a reaction in the lungs that leads to scarring, as can bacterial or mold growth in humidifiers and hot tubs.

Diseases such as tuberculosis, rheumatoid arthritis, systemic lupus erythematosis, systemic sclerosis, and bagassosis are also believed to cause lung scarring.

When the cause of lung scarring is not known, it is called idiopathic pulmonary fibrosis. Typically this is diagnosed when the patient’s work history and environment do not indicate a clear cause. Some doctors believe that scarring can be caused by infection or allergic reaction but, according to the Canadian Cancer Society, bacteria and other microorganisms related to these conditions are not usually found in the lungs of people diagnosed with pulmonary fibrosis. The reason for the connection is that scarring tends to appear after a viral-like illness.

There are some medications that can also cause scarring of the lungs. Nitiofurantoin, prescribed for urinary tract infections, amiodarone, and some medications prescribed to fight cancer have been shown to cause scarring to the lungs, according to the Canadian Lung Association.