Causes

The exact cause of Reye's syndrome is unknown, although several factors may play a role in its development. Reye's syndrome seems to be triggered by using aspirin to treat a viral illness or infection — particularly flu (influenza) and chickenpox — in children and teenagers who have an underlying fatty acid oxidation disorder.

Fatty acid oxidation disorders are a group of inherited metabolic disorders in which the body is unable to break down fatty acids because an enzyme is missing or not working properly. A screening test is needed to determine if your child has a fatty acid oxidation disorder.

In some cases, the symptoms and signs of Reye's syndrome may be duplicated by an underlying metabolic condition unmasked by a viral illness. The most frequent of these rare disorders is medium-chain acyl-CoA dehydrogenase (MCAD) deficiency. Exposure to certain toxins — such as insecticides, herbicides and paint thinner — may produce symptoms similar to those of Reye's syndrome, but these toxins don't cause Reye's syndrome.