Pneumonitis refers to the inflammation of lung tissue, a condition that encompasses a variety of causes beyond infections, such as pneumonia, which also leads to lung tissue inflammation but is specifically caused by infections. The term “pneumonitis” is more commonly applied to noninfectious sources of lung inflammation, often stemming from exposure to airborne irritants linked to one’s hobbies or workplace. Additionally, this condition can be triggered by certain medications and some forms of cancer treatment, leading to not only breathing difficulties but also a range of other physical symptoms.

The inflammation caused by pneumonitis comes in multiple types of inflammation. Among them are:

  • Acute: The onset of inflammation is sudden, and it diminishes quickly.
  • Subacute: The progression of inflammation is slow and steady.
  • Chronic: Long-term and persistent inflammation develops from inflammation.

The following types of pneumonitis includes:

  • Acute interstitial pneumonitis: Your symptoms worsen swiftly as acute interstitial pneumonitis occurs suddenly.
  • Chemical pneumonitis: When someone breathes in chemicals found in products used at home or at work, such as chemicals used in imaging tests, chlorine gas, insecticides, gasoline, and smoke, they might develop chemical pneumonitis.
  • Hypersensitivity pneumonitis: When you breathe in (inhale) allergens such as dust, mold, bacteria, or microscopic scales from animal skin, hair, or feathers (dander), you may develop hypersensitivity pneumonitis.
  • Radiation pneumonitis: Radiation pneumonitis may develop following cancer treatment with radiation therapy.

The primary indicators of pneumonitis often involve difficulty breathing, often coupled with a persistent dry cough lacking mucus production. Receiving a diagnosis typically requires specialized testing. The primary objectives of treatment are to diminish inflammation and steer clear of irritants.


The primary signal of pneumonitis is typically shortness of breath, often accompanied by a dry cough. Over time, untreated pneumonitis can progress to chronic pneumonitis, potentially leading to lung scarring (fibrosis) if left undetected or untreated.

Chronic pneumonitis signs and symptoms include:

  • Bluish discoloration or cyanosis
  • Chest pain.
  • Dry cough
  • Fatigue
  • Loss of appetite
  • Shortness of breath or dyspnea.
  • Unintentional weight loss

Anytime you have trouble breathing, regardless of the reason, seek medical attention.


Pneumonitis, an inflammation of the tiny air sacs in the lungs known as alveoli, can be triggered by a variety of irritants, ranging from chemotherapy drugs to airborne fungi. Despite the array of potential causes, the specific agent responsible for this inflammation often remains unidentified. This condition hampers the ability of oxygen to pass through the alveoli and enter the bloodstream, leading to difficulties in respiratory function.

Pneumonitis can have a wide range of potential causes. Common causes include:

  • Animal: Allergens found in animal fur, feathers, and skin have the potential to cause inflammation. One typical way to get pneumonitis is by being around feathers or bird excrement.
  • Bacteria and molds: Lung inflammation can result from exposure to certain molds and bacteria on a regular basis. Certain types of mold-related pneumonitis have been dubbed “hot tub lung” or “farmer’s lung.” Examples of molds are the ones that develop on sugar cane, hay, straw, cereals, and cheese.
  • Medications: Pneumonitis may be brought on by a number of medicines, including some antibiotics, certain chemotherapy agents, and therapies that regulate heart rate. Aspirin overuse can result in pneumonitis.
  • Radiation treatments: Pneumonitis can occur in certain patients receiving chest radiation treatment, such as those treating lung or breast cancer. In order to get ready for a bone marrow transplant, whole-body radiation treatment might sometimes result in pneumonia.

Risk factors

The following may increase the risk of pneumonitis.

  • Work or hobbies: The following occupations and hobbies have increased risks of pneumonitis:
    • Farming: Workers in a number of agricultural occupations are exposed to pesticides and aerosolized mists. One of the most frequent ways that moldy hay causes occupational pneumonitis is by airborne particle inhalation. When hay and grain are being harvested, mold particles might also be inhaled.
    • Bird handling: Individuals who deal with poultry and those who raise or breed pigeons are frequently in contact with feathers, excrement, and other elements that can lead to pneumonitis.
    • Hot tubs and humidifiers: Pneumonitis can be brought on by moldy hot tub environments because the bubbling movement creates an inhalable mist. Humidifiers in homes are another typical source of mold. Mold and bacteria can grow in an unclean environment and infiltrate you through the mist.
  • Cancer treatment: Both radiation treatment to the lungs and some chemotherapy medications can result in pneumonitis. The chance of developing irreversible lung disease is increased by the two together.