Reye's Syndrome

In the 1960s and 1970s, as many as 500 children in the United States per year were affected by Reye's syndrome, a serious, often fatal disorder.

Sick girl in bed comforted by mother
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It is still not known exactly what causes Reye's syndrome to develop, but research has shown an association between the development of the syndrome and the use of aspirin to treat flu-like illnesses and chicken pox. Reye's syndrome is not contagious.

Reye's syndrome involves dysfunction of metabolic pathways in the cell in the setting of a viral illness, and exposure to the medication aspirin seems to trigger this cycle of injury. It has been most often described in the setting of the flu and chicken pox infections.

The number of cases of Reye's syndrome in the U.S. has dropped to 50 cases per year, due to educational campaigns that resulted in a decreased use of aspirin to treat children’s illnesses. More cases of Reye's syndrome occur during flu season — the months of January, February, and March. Most (90 percent) of those affected by Reye's syndrome are under age 15, but it may also affect teenagers and adults.

Attacks the Liver and Brain

Reye's syndrome affects many organs in the body, but particularly the liver and brain. It causes damage to the cells in the liver, which interferes with the liver’s ability to remove wastes from the body. These wastes, especially ammonia, cause brain injury and swelling (encephalopathy).


Usually, the flu, viral illness, or chickenpox is almost over, and the child is starting to recover when the symptoms of Reye's syndrome begin:

First stage:

  • Loss of energy, lethargy
  • Nausea and vomiting
  • Drowsiness

Second stage:

  • Personality changes such as irritability, aggressive behavior
  • Disorientation, confusion
  • Drowsiness and lethargy may change to unconsciousness (coma)

Third Stage:

  • Coma

Fourth Stage:

  • Seizures


The diagnosis of Reye's syndrome is based on the child having had a viral illness (especially if treated with aspirin), plus the symptoms the child is having. Special blood tests for ammonia level, liver function, and other parameters.

Many types of illnesses and disorders have symptoms similar to Reye's syndrome, so medical providers may diagnose the symptoms as something else. One important clue to Reye's syndrome is the viral illness that was present before the symptoms started.


Reye's syndrome is a serious illness. As many as 50 percent of individuals who develop the syndrome die from it. The individual with Reye's syndrome needs intensive care to reduce the brain swelling quickly to prevent permanent brain damage, and to prevent other complications from the disorder. Early diagnosis and prompt treatment will improve the individual’s prognosis.


Since the use of aspirin and aspirin-containing products is associated with increased risk of Reye's syndrome, The National Reye's Syndrome Foundation, the Surgeon General, the FDA, and the CDC recommend that those medicines not be given to children or teenagers who have the flu, an illness with a fever, or chicken pox.

You may recognize some brands, such as Bayer or St. Joseph, as aspirin, but there are other products that contain aspirin, such as Anacin, Excedrin, Dristan, and Pamprin or contain chemicals like aspirin, such as in Pepto-Bismol. If you aren’t sure if something contains aspirin, ask your healthcare provider or pharmacist. The National Reye’s Syndrome Foundation also has a list of products containing aspirin that can help you.

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  • The National Reye’s Syndrome Foundation. What is Reye’s Syndrome