How long is it dangerous for a child to have a high fever of 39°C?

High fever generally refers to a high body temperature. There is no specific time frame for when a child's high fever of 39°C becomes dangerous; the risk must be assessed based on individual circumstances.

When a child has a high fever of 39°C, damage to the body may occur after just half an hour. If the high fever lasts more than 24 hours, it could cause harm to health. Because children are young and their central nervous systems are not fully developed, a sustained fever of 39°C for over half an hour may affect the nerves, potentially leading to symptoms such as febrile seizures and abnormal brain function. In severe cases, it could even result in septic shock. Therefore, prompt medical evaluation is essential once a high fever of 39°C occurs. Follow the doctor’s advice, use medications appropriately, and prevent serious harm to health.

During treatment, ensure proper local warmth and protection to avoid chilling the body, which could worsen existing symptoms.