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Radiation Pneumonitis

  • Amy Scholten, MPH
Publication Type:


Radiation Pneumonitis

(Radiation-induced Lung Injury)


Radiation pneumonitis is an inflammation of the lung tissue. It often appears between 6 and 24 weeks after radiation therapy.

If left untreated, pneumonitis can lead to lasting lung or breathing problems.


Radiation pneumonitis is most often caused by radiation therapy to the lungs or nearby areas.


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Risk Factors

This condition is most common in people who have radiation therapy for lung cancer. It is also more common in older adults. Other things that raise the risk of radiation pneumonitis are:

  • Having other lung disorders, such as chronic obstructive lung disease (COPD)
  • High doses of radiation treatment
  • Larger amount of lung tissue exposed to radiation
  • Previous radiation therapy or lung injury
  • Other recent or current treatments, such as chemotherapy


Radiation pneumonitis does not always cause symptoms. When symptoms happen, breathing problems are the most common. They may happen with activity or rest and get worse over time.

Other symptoms may be:

  • Lasting dry cough, which may range from mild to severe
  • Chest pain
  • Increasing amounts of sputum, with or without blood
  • Fever
  • Muscle aches
  • Increasing weakness


The doctor will ask about symptoms, past health, and recent treatment. A physical exam will be done. This includes listening to the lungs. Other conditions need to be ruled out. Tests may include:

  • Blood tests—to look for signs of infection or imbalances
  • Pulmonary function tests —to assess function of the lungs
  • Swabs to test secretions in the throat—to look for infection
  • Sputum culture—to look for infection

Imaging tests to view the lungs and surrounding structures are:


When caught early, the goal is to stop inflammation before it causes harm. Treatment depends on the severity of the radiation pneumonitis. Prompt treatment may lead to a full recovery in most people.

Treatment may include:

  • Corticosteroids to reduce lung inflammation
  • Medicines to suppress the immune system

Other treatments may help ease symptoms until pneumonitis is healed. Options are:

  • Vitamin A, C, and E supplements
  • Cough medicines
  • Oxygen therapy to increase the amount of available oxygen

Some medicines or chemotherapy drugs can make pneumonitis worse. These treatments may need to be stopped or changed.

Lung function will also be checked regularly to look for changes.


Radiation is carefully measured. The goal is to give the least but most effective amount to the smallest area of tissue.

Finding and treating symptoms early leads to better outcomes. It is important to monitor any side effects from radiation therapy.





  • Hanania AN, Mainwaring W, et al. Radiation-induced lung injury: assessment and management. Chest. 2019;156(1):150-162.
  • Radiation exposure and contamination. Merck Manual Professional Version website. Available at: https://www.merckmanuals.com/professional/injuries-poisoning/radiation-exposure-and-contamination/radiation-exposure-and-contamination.
  • Radiation-induced lung injury. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/radiation-induced-lung-injury.
  • Radiation pneumonitis. Oncolink website. Available at: https://www.oncolink.org/cancer-treatment/radiation/side-effects-of-radiation-therapy/radiation-pneumonitis.
  • Radiation therapy. American Cancer Society website. Available at:https://www.cancer.org/treatment/treatments-and-side-effects/treatment-types/radiation.html.


  • Mohei Abouzied, MD, FACP
Last Updated:

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.