Causes of Pneumonitis

What are the Causes of Pneumonitis?

• Pneumonia (infection by bacteria, fungi or viruses)
• Inhalation of of stomach contents while vomiting (aspiration pneumonitis)
• Hypersensitivity pneumonitis caused by inhalation of an allergy causing substance - eg, humidifier lung, farmer's lung, bird fancier's lung.

• Autoimmune connective tissue diseases – rheumatoid arthritis, scleroderma, systemic lupus erythematosus (SLE)
• Adverse reaction to drug or toxic chemical eg chlorine, ammonia gas, interferon therapy, amiodarone, nitrofurantoin, aspirin overdose
• Radiation therapy to chest for cancer
• Sepsis caused by overwhelming infection

Risk Factors of Hypersensitivity Pneumonitis

• Bird handlers – Inhalation of bird feathers or bird droppings
• Farmers – Inhalation of droplets of pesticides or airborne particles in moldy hay
• Hot tubs and humidifiers – Inhalations of mold from poorly maintained humidifiers and hot water tubs