Skip directly to search Skip directly to A to Z list Skip directly to navigation Skip directly to page options Skip directly to site content

Acute Radiation Syndrome (ARS): A Fact Sheet for the Public

Button the Health Effects of Radiation
Button Radiation Treatments
Button Radiation Health Information for Specific Groups

Acute Radiation Syndrome (ARS), or radiation sickness, is a serious illness that can happen when a person is exposed to very high levels of radiation, usually over a short period of time. The amount of radiation that a person’s body absorbs is called the radiation dose.

People exposed to radiation will get ARS only if:

  • The radiation dose was high
  • The radiation was able to reach internal organs (penetrating)
  • The person's entire body, or most of it, received the dose
  • The radiation was received in a short time, usually within minutes

Symptoms of ARS

  • Symptoms of ARS may include nausea, vomiting, headache, and diarrhea.
    • These symptoms start within minutes to days after the exposure, can last for minutes up to several days, and may come and go.
    • If you have these symptoms after a radiation emergency, seek medical attention as soon as emergency officials determine it is safe to do so.
  • After the initial symptoms, a person usually looks and feels healthy for a period of time, after which he or she will become sick again with variable symptoms and severity that vary depending on the radiation dose that he or she received.
    • These symptoms include loss of appetite, fatigue, fever, nausea, vomiting, diarrhea, and possibly even seizures and coma.
    • This seriously ill stage may last from a few hours up to several months.
    • People who receive a high radiation dose also can have skin damage. This damage can start to show within a few hours after exposure or it may be delayed for several days. It can include swelling, itching, and redness of the skin (like a bad sunburn) or may be more severe and include blisters or ulcers.
      • The skin may heal for a short time, followed by the return of swelling, itching, and redness days or weeks later.
      • Complete healing of the skin may take from several weeks up to a few years.
      • The time for skin to heal depends on the radiation dose the person’s skin received.
      • People who receive a high radiation dose to all or part of the body also may experience temporary hair loss. It may take several weeks for the hair to grow back.

Treatment of ARS

  • Treatment of ARS focuses on reducing and treating infections, maintaining hydration, and treating injuries and burns. Some patients may benefit from treatments that help the bone marrow recover its function.
  • The lower the radiation dose, the more likely it is that the person will recover from ARS.
  • The cause of death in most cases is the destruction of the person's bone marrow, which results in infections and internal bleeding.
  • For survivors of ARS, the recovery process may last from several weeks up to 2 years.
  • Cutaneous Radiation Injury (CRI) happens when exposure to a large dose of radiation causes injury to the skin. A doctor will suspect the presence of a CRI when a skin burn develops in a person who was not exposed to a source of heat, electrical current, or chemicals.

radiation symbol iconPeople with ARS typically also have some skin damage. This damage can start to show within a few hours after exposure and can include swelling, itching, and redness of the skin (like a bad sunburn).

There also can be hair loss. As with the other symptoms, the skin may heal for a short time, followed by the return of swelling, itching, and redness days or weeks later. Complete healing of the skin may take from several weeks up to a few years depending on the radiation dose the person's skin received.

Ready: Prepare. Plan. Stay Informed.Social Media at CDC Emergency

Top