Fever may develop at various speeds and may reach heights ranging from 100.4 degrees to 104 degrees Fahrenheit (38 degrees and 40 degrees Celsius) or higher. The speed and height of a temperature is not necessarily indicative of the seriousness of the underlying disease. The fever may fluctuate or remain mostly steady throughout a child’s illness.

Children who have a fever are likely to experience several associated symptoms. Typically, they will perspire, causing the skin to become hot and moist as body temperature increases. They also may have a flushed appearance, and may become lethargic or fatigued. Loss of appetite (anorexia), chills (resulting from the body’s attempt to generate extra heat), muscle aches and headaches often accompany fever.

A febrile seizure may occur in children whose fever rises very quickly and reaches heights of around 105 degrees Fahrenheit (40.6 degrees Celsius) or more. This type of seizure most often affects children between the ages of 6 months and 3 years. Symptoms include brief loss of consciousness and convulsions. However, the effects of a febrile seizure are usually not permanent.

Fevers between 103 degrees and 106 degrees Fahrenheit (39.4 degrees and 41.1 degrees Celsius) may trigger hallucinations, confusion, irritability and convulsions.