Signs and symptoms

The symptoms of Reye's syndrome usually begin a few days after a viral infection. We detail the early signs and symptoms of Reye's syndrome and offer advice to parents about how to respond to these symptoms, or fever in a child.

What are the early stages of Reye’s Syndrome?

The symptoms of Reye’s syndrome usually begin a few days after a viral infection. These include:

  • Persistent or continuous vomiting, and/or:
  • Signs of cerebral oedema (brain swelling):
    • Listlessness (a lack of interest or enthusiasm)
    • Loss of Energy
    • Drowsiness
    • Delirium (a severe state of mental confusion and anxiety sometimes associated with hallucinations)
    • Convulsions (fits)
    • Coma
  • Personality changes:
    • Irritability
    • Aggressive behaviour
    • Disorientation
    • Confusion
    • Irrational behaviour

Reye’s syndrome should be suspected if a child displays all or part of this pattern of symptoms a few days after the onset of a viral infection such as ‘flu’ or chickenpox. Fever is not usually present. Many diseases have similar features. Medical staff who do not have experience of Reye’s syndrome may initially suspect encephalitis (inflammation of the brain), meningitis (inflammation of the protective membranes surrounding the brain and spinal cord), poisoning, mental illness or even drug abuse. In infants the symptoms of Reye’s syndrome may not follow a typical pattern; for example, vomiting is less common. However, it should be emphasised that it is in infants that the “Reye-like syndromes” are most likely to occur.

Reye's syndrome can successfully be managed with a good outcome if diagnosed early and meticulously treated.

What should be done if symptoms of Reye’s Syndrome develop?

If your child shows symptoms of Reye’s syndrome and:

  • loses consciousness
  • has a fit or convulsions (violent, irregular limb movements)

Dial 999 to ask for an ambulance, or go straight to your nearest accident and emergency (A&E) department.

Consult your general practitioner (GP) immediately if after having a cold, flu or chickenpox, your child is:

  • vomiting repeatedly
  • unusually tired
  • displays personality or behavioural changes

Tell your GP if for whatever reason your child has been given a product containing aspirin.

Ideally take the aspirin container/patient information leaflet with you. This would alert the GP to consider Reye’s syndrome as part of his/her diagnosis. Statistics indicate a better chance of survival when Reye’s syndrome is diagnosed and treated in its earliest stages. The later the diagnosis, the more advanced the coma, and the chances of survival and full recovery are greatly reduced.

Further advice about looking after a sick child can be found on Looking after a sick child (NHS).

What can I do if my child has a fever and I cannot use aspirin?

Fever is a normal response to infection. It may actually help your child to fight off viral illness. The NHS advise as an aid to preventing Reye’s syndrome that if your child or teenager has ‘flu’ (influenza) or other viral infections, paracetamol or ibuprofen can be used to reduce their fever and relieve pain.

However, ibuprofen is not recommended for those with a history of asthma, kidney disease, or liver disease. Always read carefully the directions on the packet, bottle, or the patient information leaflet.

Check with your GP or pharmacist if you are unsure.

There is no need to undress your child or sponge them down with tepid water. Research shows that neither actually helps reduce fever. Avoid bundling them up in too many clothes or bedclothes.

Keep the room at moderate temperature and encourage the child to drink liquids such as water and non-fizzy soft drinks.

If the fever does not respond to any of these measures, obtain advice urgently from your doctor. For further information see Reye’s Syndrome (NHS).

Children under 12 months of age who have a fever should not be treated without medical advice.

Date of next review: December 2021