Understanding the Difference Between Pneumonitis vs. Pneumonia

Pneumonitis, is often confused with pneumonia, but these are similar ailments but not the same.  While pneumonia is a type of infection which causes lung inflammation, pneumonitis is a general term to describe inflammation in pulmonary, or lung, tissue. So technically pneumonia would fall into the category of being a type of pneumonitis, but generally most physicians look to other causes of lung inflammation when referring to a patient having "pneumonitis."  These other causes vary dramatically, from airborne irritants, to different types of cancer treatments, and even some antibiotics or aspirin.  Airborne irritants are probably the most common cause of pneumonitis and can stem from being exposed to a type of chemical, dust, or bacteria.


The exposure to these irritants causes inflammation in the alveoli of the lungs.  Alveoli are tiny air sacs that aid in transferring oxygen to the bloodstream.  When these air sacs become inflamed, people find it difficult to breath, and can soon start to experience a dry cough which can be thought of as the most common symptom of pneumonitis. If pneumonitis is left untreated, chronic pneumonitis or alveolar inflammation can ensue and lead to scarring of the lungs. It is probably safe to contact your doctor anytime you have difficulty breathing, no matter what the cause might be just to stay ahead of any serious complications.

The most common symptoms of chronic pneumonitis are:

·         Shortness of breath

·         Cough

·         Fatigue

·         Loss of appetite

·         Unintentional weight loss


What causes pneumonitis?

Compared to pneumonia, pneumonitis is any inflammation of the lung tissue without the presence of infections.  As mentioned, irritants like mold or pharmaceutical drugs can cause this inflammation in the alveolar sacs of the lungs.   More specifically, these pulmonary irritants include:

·         Drugs: these can range from antibiotics, to chemotherapy drugs, to certain heart medications.  Higher than normal dosing of aspirin can also cause the inflammation of pneumonitis.

·         Mold, hay and other airborne material: Repeated exposure to molds, hay or airborne particles can cause the lungs to become inflamed.

·         Birds: Exposure to bird feathers, and the particles in the feathers can cause irritation – especially in bird handlers who are exposed over longer period of time.

·         Radiation treatments: Some people who need to receive radiation therapy to the chest, for illnesses such as for breast or lung cancer, the therapy can cause pneumonitis.

Risk factors:

Some occupations and hobbies carry higher risks of pneumonitis, including:

  • Farming: Hay, and grassy material can lead to “farmer’s lung”, where all these inhaled particles irritate the lungs immensely.  Some farming operations also expose workers to aerosolized mists and pesticides.
  • Bird handling: Poultry workers are exposed to feathers and other materials that can cause pneumonitis.
  • Humidifiers and hot tubs: Moldy conditions in hot tubs can trigger pneumonitis because the bubbling action makes a mist that can be inhaled. Home humidifiers are another common reservoir for mold.
  • Cancer treatments: some chemotherapy and radiation therapy treatments can irritate and inflame the lungs.  This inflammation leads to pneumonitis and along with the treatment can also put you at risk for developing lung disease.