When does a fever become dangerous for a teen?

Over 102: Actually, fever is rarely dangerous to older teens and adults, it is the underlying disease that is either dangerous or not. Young children can be prone to seizure with fever. Older teens and adults may be uncomfortable, but rarely injured by fever alone, under 102. However, treat the fever for comfort, and depending on concurrent symptoms, see your doctor.

? danger ?: Fever is a natural body response to illness as it turns on the immune system to fight disease. Fever increases heart rate to circulate blood with germ fighters & breathing to gain more oxygen. It usually tops out around 105 before the kid is delirious but the fever itself doesn't damage the kid at that point. Uncontrollable fever above 105 can begin to alter some body functions.