Radiation poisoning symptoms: What are the early signs of radiation poisoning?

Medically reviewed by Ashley WongPharm. D.
Licensed Pharmacist
Updated Oct. 27, 2023  •  Published Sep. 11, 2023
Fact Checked
Radiation poisoning symptoms: What are the early signs of radiation poisoning?

Overview: What does radiation poisoning feel like?

Radiation poisoning (acute radiation syndrome, or ARS) is a serious and life-threatening result of full-body exposure to a large radiation dose in a short period of time. Events that can cause radiation poisoning are rare, most commonly atomic bomb explosions or nuclear power plant accidents like Chernobyl. Though rare, these events can expose many people to a large amount of radiation, such as X-rays and gamma rays. The first symptoms of radiation sickness are typically nausea, vomiting, headache, diarrhea, and sometimes skin redness and pain that look and feel like a burn. These symptoms can start within minutes, hours, or days of exposure. After these initial symptoms, people feel normal and healthy for a few hours, days, or weeks. Then they get very sick. The symptoms will depend on the severity of the exposure. Loss of appetite, weight loss, bleeding, and infections are examples of common symptoms. For very large radiation doses, symptoms are very severe and sometimes lethal. 

Key takeaways:

  • Radiation poisoning is a rare health condition that can affect anyone regardless of age, sex, race, or ethnicity. 

  • Early signs of radiation poisoning include nausea, vomiting, headache, diarrhea, and sometimes skin redness and pain.

  • All symptoms of radiation poisoning or radiation exposure require immediate medical attention.

  • Radiation poisoning is caused by exposure to penetrating radiation. Risk factors are hard to determine because nuclear weapon incidents, nuclear power plant accidents, and other events that cause radiation exposure are unpredictable.

  • Radiation poisoning requires a medical diagnosis.

  • Radiation poisoning generally requires treatment. Radiation poisoning symptoms may resolve with treatment in a few days or months, but survivors can experience delayed effects throughout their lives.

  • Treatment of radiation poisoning may include emergency treatments, supportive treatments, growth factors to stimulate blood cell production, blood transfusions, bone marrow transfusions, anti-nausea drugs, antibiotics, antifungal drugs, antiviral drugs, diarrhea medications, and numerous other treatments and possible surgeries.

  • Untreated radiation poisoning could result in complications like infections, bleeding, dehydration, electrolyte imbalances, and death.

  • Save on prescriptions for radiation poisoning with a SingleCare prescription discount card.

What are the early signs of radiation poisoning?

The earliest signs of radiation poisoning occur within minutes, hours, or days after exposure. These signs typically include:

  • Nausea

  • Vomiting

  • Loss of appetite

  • Diarrhea

  • Headache

People may also notice other symptoms:

  • Skin redness and pain

  • Hair loss

  • Loss of consciousness (for extremely high radiation doses)

  • Confusion (for extremely high radiation doses)

The time it takes for these initial symptoms to appear usually depends on the size of the radiation dose absorbed by the body. Higher levels of radiation produce symptoms more quickly than lower doses. Extremely high doses can cause symptoms within minutes. Initial symptoms will be more severe with a higher dose.

Other radiation poisoning symptoms

Radiation poisoning symptoms will depend on the size of the dose absorbed.

The first signs of radiation poisoning are called the prodromal stage or N-V-D stage. These symptoms occur within minutes to days after exposure:

  • Nausea

  • Vomiting

  • Loss of appetite

  • Diarrhea

  • Fever

  • Headache

  • Skin redness (in some people)

These symptoms eventually improve, and it can feel like the sickness has passed. This symptomless stage is called the latent stage and can last from a few minutes to several weeks, depending on the size of the absorbed radiation dose. Again, the larger the dose, the shorter the latent period. With an extremely high dose, there may be no latent period.

At the end of the latent stage, people get very sick due to the delayed effects of the original exposure on bone marrow, the intestines, and other tissues. This is called the manifest illness stage. Symptoms will vary depending on the severity of the exposure, but common symptoms includee:

  • Loss of appetite

  • Fever

  • Feeling very sick (malaise)

  • Bleeding, bruising, and symptoms of internal bleeding

  • Hair loss

  • Skin redness (in some people)

People exposed to high doses of radiation may also have symptoms such as:

  • Severe nausea

  • Vomiting

  • Diarrhea

  • Watery diarrhea

  • Bleeding

  • Dehydration

  • Electrolyte imbalance

  • Symptoms of sepsis

If the original radiation exposure is very high, people may also feel other very severe symptoms, including:

The manifest illness stage can last from several hours to many months. Survival depends on the exposure and how quickly treatment is started. At lower exposures, people usually recover with treatment. Extremely high doses are almost always fatal. 

Stages of radiation poisoning: How can I tell which one I have?

Radiation poisoning has four distinct stages:

  • The prodromal, or N-V-D, stage involves the initial effects of high-dose radiation on the body. Symptoms usually include nausea, vomiting, diarrhea, and loss of appetite. The exposed skin may turn red and hurt like a sunburn or burn. These symptoms typically start within minutes of an extremely high-dose exposure but could start days after a lower-dose exposure.

  • The latent stage is symptomless. The nausea and vomiting go away, and people generally feel as well as before the exposure. This stage can last from a few hours to a few weeks

  • The manifest illness stage is what most people think of as radiation sickness. At this point, radiation damage to the body’s tissues manifests and produces symptoms.. There are three classic syndromes that can occur during the manifest illness stage. The syndrome people develop depends on the absorbed dose of radiation. 

  • Most people with radiation sickness survive, but recovery can take a few weeks to two years. Some people may need to see a doctor regularly to monitor their recovery. Others may need continual care for several months.

Types of radiation poisoning

The total absorbed dose of radiation will determine how sick people will get during the manifest illness stage of the disease. 

Hematopoietic (bone marrow) syndrome

Lower doses will only affect the bone marrow. The ionizing radiation causes the bone marrow to shut down and stop producing red blood cells, white blood cells, and platelets. This makes people vulnerable to infections and bleeding. With treatment, most people will recover within a few weeks to two years

Gastrointestinal syndrome

Higher doses can affect the digestive system. People become susceptible to infections, bleeding, dehydration, and electrolyte imbalances. With treatment, some people may recover from this syndrome but survival is unlikely

Cardiovascular and central nervous system syndrome

Very high doses will affect the heart,, the blood vessels, and the nervous system. This syndrome usually starts within hours of the original exposure. Survival is not expected, as most pass away from swelling in the brain or a complete collapse of the cardiovascular system. 

When to see a doctor for radiation poisoning symptoms

See a doctor if you experience any symptoms of radiation poisoning or if you have been accidentally exposed to radiation. Even if the dose is not high enough to produce symptoms, it may still have delayed effects that happen years later. Immediate treatment, such as potassium iodide pills, may mitigate these delayed effects.

The diagnosis of radiation exposure is complicated. A history and examination can help identify symptoms, such as early radiation poisoning or injury symptoms. If radiation poisoning is suspected, hospitalization may be required. The healthcare professional will start taking blood tests every few hours to see if the blood counts are going down, a sign that radiation has affected the bone marrow. 

Complications of radiation poisoning

Radiation poisoning is a severe and life-threatening illness. Untreated radiation poisoning can result in complications such as infections, bleeding, sepsis, dehydration, or electrolyte imbalances that can be fatal.

How to treat radiation poisoning symptoms

Radiation poisoning often requires hospitalization and intensive care during the manifest illness stage of the disease. Some people may be admitted to a hospital immediately after exposure. Intensive care caninvolve:

Depending on the severity of the manifest illness stage, people who survive may require supportive care or follow-up care for weeks or months.

Signs radiation poisoning is getting better

After surviving the worst symptoms of radiation poisoning, full recovery may take a few weeks, a few months, or even a couple of years. Most people will feel better during this time, but some may require monitoring or supportive care. Even after full recovery, delayed effects can occur in the following years and decades.

Most importantly, see a doctor immediately

Radiation exposure of any kind is a health hazard. If you’ve been unintentionally exposed to a radiation source, immediately see a healthcare professional. If you have symptoms following that exposure, go to the emergency room. The absorbed radiation dose will likely not be high enough to have adverse health effects. However, early monitoring and treatment ensure the best outcomes.

FAQs about radiation poisoning symptoms

How long do the effects of radiation stay in your body?

After a bout with radiation poisoning, it takes a while for cells in the body to fully recover. For people exposed to lower doses, most people with radiation poisoning fully recover in a few months to two years with treatment. However, they are likely to experience unpredictable delayed effects over the rest of their lives.

What are the long-term symptoms of radiation?

Radiation damages cellular DNA. This damage is responsible for radiation poisoning symptoms and it can affect the body and internal organs months, years, or even decades after exposure to high radiation levels. Healthcare providers call these effects delayed effects of acute radiation exposure (DEARE). They include leukemia, cancer, thyroid disease, cataracts, and lung scarring,. Some treatments during the worst phase of radiation sickness can help prevent some of these later effects and increase lifespan after recovery. Additionally, people who have lived through radiation sickness are more likely to have mental health problems such as anxiety, depression, and post-traumatic stress disorder (PTSD).

When are radiation side effects the worst?

The effects of radiation sickness are at their worst in the manifest illness stage. This can occur minutes or hours after exposure. For treatable radiation sickness, the worst symptoms usually occur within a few hours, days, or weeks after exposure.

What’s next? Additional resources for people with radiation poisoning symptoms

Test and diagnostics

Treatments

Scientific studies and clinical trials

Medically reviewed by Ashley WongPharm. D.
Licensed Pharmacist

Ashley Wong, Pharm.D., has worked for healthcare companies where she translated complex drug information into easy-to-understand language for patients. She also served as a Senior Medical Information Specialist at a medical communications company, where she delivered clinically accurate drug information to healthcare providers and patients and compiled adverse event reports in accordance with the FDA's reporting guidelines.

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