Radiation Emergencies

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

Possible Health Effects of Radiation Exposure and Contamination Medical Countermeasures (Treatments) for Radiation Exposure and Contamination 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, canlast 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 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.

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More Information

  • Infographic: Radiation Contamination Versus Exposure
  • Infographic: Decontamination for Yourself and Others

Resources for Professionals

  • Acute Radiation Syndrome: A Fact Sheet for Physicians
  • Video: Just-In-Time Training for Hospital Clinicians
  • Radiation Injury Treatment NetworkExternal Web Site Icon
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