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Reye Syndrome

Medically reviewed by Last updated on Jul 11, 2022.

What is Reye Syndrome?

Harvard Health Publishing

Reye syndrome is a very rare disorder that damages many parts of the body, especially the brain and the liver. For unknown reasons, the parts of the cells that make energy (mitochondria) stop working correctly, which causes severe illness. The most serious problems are swelling of the brain and problems with the breakdown of fat, which results in build up in the liver and other organs. The illness can be fatal, especially if not detected early and treated appropriately. 

Although Reye syndrome can occur at any age, it most often affects children between the ages of 3 and 12. 

Reye syndrome typically occurs several days after the child is recovering from a viral infection, such as the flu, common cold, or chickenpox. It also can develop while the child is still sick, a few days after the viral illness began. While the exact cause of Reye syndrome is not known, researchers believe that it may be due to an abnormal response to aspirin or aspirin-containing products taken during a viral illness. For this reason, never give aspirin or aspirin-containing medicines to children with fever or a flu-like illness.


Symptoms can include: 

  • Frequent vomiting (every couple of hours over a day or two) that does not stop even when not eating or drinking 
  • Extreme sleepiness (lethargy) 
  • Confusion 
  • Irritability and combativeness 
  • Rapid breathing (hyperventilation) 
  • Loss of consciousness 
  • Seizures 

In infants, the symptoms of Reye syndrome may not follow this typical pattern. For example, infants with Reye syndrome do not always vomit. 


The doctor may suspect a child has Reye syndrome based on the symptoms and a history of very recent viral illness. Blood tests, including tests of liver function, will be done. Other tests often are necessary to confirm the diagnosis, including: 

  • A biopsy of the liver — A small piece of the liver is removed and examined. 
  • A lumbar puncture (spinal tap) — A needle is used to remove fluid from the spinal cord so it can be examined. 

Reye syndrome can be difficult to diagnose. It is sometimes mistaken for other serious illnesses, such as encephalitis, meningitis, uncontrolled diabetes, or drug overdose. 

Expected Duration

How long it takes to recover from Reye syndrome depends on how much the brain has swelled. People with mild disease usually recover quickly and completely.


Although a clear link between aspirin and Reye syndrome has not yet been proven, experts agree that to prevent Reye syndrome, the safest approach is never to give aspirin or aspirin-containing medicines to children. Read labels carefully. Look for the word aspirin and other words that also mean aspirin: acetylsalicylate, acetylsalicylic acid, salicylic acid and salicylate. When necessary, non-aspirin medicines, such as acetaminophen (Tylenol), should be used instead.


Treatment depends on the symptoms, but all patients with Reye syndrome need to be treated in a hospital and monitored closely. Treatment focuses on protecting the brain against irreversible damage by preventing or reducing brain swelling. 

Specific treatments may include: 

  • Giving fluids containing sugar and salts intravenously (into a vein) 
  • Medications (for example, to decrease brain swelling or treat problems caused by liver failure) 
  • Intubation (inserting a tube that helps with breathing) 
  • Patients with more serious disease typically are treated in an intensive care unit. 

When To Call a Professional

Reye syndrome is a serious, life-threatening condition. If your child has had a viral infection and has any symptoms of Reye syndrome, call your doctor immediately. It is an emergency!


With early diagnosis and treatment, the chances of recovery are excellent. Some people will recover fully, while others may have permanent brain damage. The outlook is poorer for people with Reye syndrome who rapidly become unconscious. If diagnosis and treatment are delayed, the chances of successful recovery and survival are less. If Reye syndrome is not treated, death is common, usually within a few days.

Additional Info

American Academy of Pediatrics (AAP)

American Medical Association (AMA)

Centers for Disease Control and Prevention (CDC)

National Reye's Syndrome Foundation

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.