According to the Mayo Clinic, a fever is not dangerous in adults until it reaches above 103 degrees Fahrenheit. Fevers are a normal process that helps to activate the body's immune system and fight infection, according to Healthy Children. While the exact temperature of a fever does not correlate with its seriousness, it is important to keep an eye on a temperature to ensure it remains in a healthy range.
In an adult, a fever under 103 F is little cause for concern, although it can be quite uncomfortable, causing aches and pains throughout the body. The Mayo Clinic recommends using fever-reducing over-the-counter medicines for any fever over 102 F in an adult to get comfort and rest. Until the fever breaks, medicine only provides temporary relief to help keep a fever down. If a fever lasts for more than three days, a doctor should be consulted.
According to the Mayo Clinic, children under 3 months of age should see a doctor if they have a fever greater than 100.4 F, while children over 3 months but under 2 years should see a doctor if they have a fever over 102 F. Any child over the age of 2 who maintains a fever for over three days should also see a doctor, as this can be the sign of an underlying condition that requires medical treatment.