Pneumonitis (noo-moe-NIE-tis) is a general term that refers to inflammation of lung tissue. Although pneumonia is technically a type of pneumonitis because the infection causes inflammation, most doctors are referring to other causes of lung inflammation when they use the term "pneumonitis."
Factors that can cause pneumonitis include exposure to airborne irritants at your job or from your hobbies. In addition, some types of cancer treatments and dozens of drugs can cause pneumonitis.
Difficulty breathing — often accompanied by a dry (nonproductive) cough — is the most common symptom of pneumonitis. Specialized tests are necessary to make a diagnosis. Treatment focuses on avoiding irritants and reducing inflammation.