|Classification and external resources|
Pneumonitis was listed as the one of the top 15 leading causes of death (at number 15) in the United States as of 2010, overtaking homicide, which dropped off the list. This was due to a number of factors, including an increase in the population of people over 75, for whom pneumonitis is a common cause of death.
- Viral infection. As one example, measles can cause severe pneumonitis, and ribavirin has been proposed as a possible treatment.
- Radiation therapy
- Inhaling chemicals, such as Sodium hydroxide 
- Adverse reaction to medications
- Hypersensitivity to inhaled agents
- Inhalation of spores of some species of mushroom (Bronchoalveolar allergic syndrome)
- Mercury exposure
- Overexposure to Chlorine
- Drugs such as Afatinib, Crizotinib, Everolimus, Minocycline hydrochloride, Olaparib , Trametinib
- Hypersensitivity pneumonitis, also known as extrinsic allergic alveolitis or EAA
- Stedman's medical dictionary (28th ed.). Philadelphia: Lippincott Williams & Wilkins. 2006. ISBN 978-0-7817-6450-6.
- Mayo Clinic
- STOBBE, MIKE (12 January 2012). "Homicide drops off US list of top causes of death". Yahoo News/Associated Press. Retrieved 12 January 2012.
- Patient UK