A high fever can cause brain damage in children

What the research found

Australian health guidance says fever is a normal response to infection and is usually harmless. Febrile seizures, which can happen when a child has a fever, are described as not causing brain damage. A 2022 review agrees that they seldom result in brain damage.

Guidance also says the danger rises at very high temperatures. A fever of about 41.5°C or more is called extremely dangerous and could trigger convulsions. One page says a fever of 42.4°C or higher, particularly in the elderly, can permanently damage the brain. It does not give a separate figure for children.

Context matters. A 2008 meta-analysis of people with stroke or other neurological injury, not specifically children, found fever was linked to worse outcomes. Guidelines for a rare inherited metabolic condition say fever can help trigger brain damage in young children who have it. A 2016 review found many parents fear fever-related brain damage, even though guidelines say fever is not in itself dangerous.

What it doesn’t mean

• This does not mean a high fever can be ignored. See a doctor if your child's temperature is over 40°C, they seem to be getting sicker, or they are confused or drowsy.
• Call an ambulance on 000 if a seizure lasts longer than 5 minutes, if it is your child's first seizure, or if they do not wake up afterwards.
• The fever studies in people with brain injury show an association, not proof that fever caused the harm. They were not studies of children with ordinary fevers.