The cause of lung scarring is not always known, but potential causes include environmental pollutants, certain medicines, some chronic illnesses, infections and radiation treatment. Research shows that 9 out of 10 people with lung scarring also have gastroesophageal reflux disease, reports the National Institutes of Health.
When the cause of lung scarring, also known as pulmonary fibrosis, is unknown, doctors often refer to the condition as idiopathic pulmonary fibrosis. Medications that have been known to cause lung scarring include certain chemotherapy medicines, such as methotrexate and bleomycin, certain heart medications, such as amiodarone or propranolol, and some antibiotics, such as nitrofurantoin and sulfasalazine, notes Mayo Clinic. Radiation treatment in the chest area for cancers such as lung or breast cancer is another possible cause of lung fibrosis.
Medical conditions that can cause lung scarring include infections affecting the lungs, such as pneumonia or tuberculosis. Chronic inflammatory conditions such as sarcoidosis and other chronic conditions such as lupus and rheumatoid arthritis can also damage the lungs, causing scars, adds Medicinenet.
Environmental toxins and pollutants that damage and scar the lungs include silica dust, grain dust and asbestos fibers, especially when breathed in at a workplace over an extended period of time, mentions Mayo Clinic.