A very common question from parents is “when do I need to worry about a fever?” There are many misconceptions about fever and its perceived danger. First, it is important to understand that fever is a normal response of a healthy immune system, and an important one, that helps us to actually fight off infections, both viral AND bacterial. This is because the heat that our bodies generate during a fever actually impairs a virus or bacteria’s ability to reproduce. Also, we have many proteins in our bodies that work to fight off infection that work best in a “hot” environment. So, in many ways your child’s fever is helpful and good. For this reason, I always let parents know that our main reason for treating fever is to make a child more comfortable. If your child is sleeping comfortably and you happen to note that he or she has a fever, you do not need to wake your child to give them medicine.
The second thing to know is that in a normal person, with a normal ability to sweat and give off heat, the body will not be able to generate a level of fever that would cause damage. (This does not apply for people born without the ability to sweat, for people in environments where they are not able to sweat, or people with heat stroke).
A common concern for parents is a concern about febrile seizures (fever seizures). Febrile seizures can occur in young children, most commonly between the ages of 6 months and 5 years. These seizures are not actually related to how high a fever goes, but rather to how rapidly the temperature rises. A simple febrile seizure (lasting less than 15 minutes, consisting of a generalized seizure with whole body shaking) is not associated with any risk for brain damage or epilepsy later in life and requires no evaluation for the seizure itself. In much the same way, doctors want to see your child to evaluate WHY they have a fever, not because they are concerned about the fever itself. In instances where a child presents with a febrile seizure, the physician should search for the cause for the fever, and treat that as indicated.
In young infants (less than 2 months of age) a fever of any level should be evaluated by a doctor. Fever is defined as a temperature of 100.4 F or greater (38 degrees Celcius). Children this age need to be evaluated because they have not yet received vaccines and have immature immune systems. They can have serious infections in the blood, urine or spinal fluid (meningitis) and have no symptom other than a low-grade fever. In older children (3 months to 3 years old) who are unvaccinated, a fever of greater than 102 F should be evaluated by a physician for the same reason. In older children who have received all of their vaccines, there is no specific “level” at which fever must be evaluated. In a child who is over 2 months, who is otherwise well-appearing (drinking well, urinating normally, breathing well) a fever should be evaluated if it persists for more than 3 days without showing signs of improvement.
Lastly, a common misconception is that only bacteria can give children high fevers. Viruses can cause fevers just as high as bacterial infections can, even to 104-105 degrees. A high fever is not an absolute indicator of a bacterial infection, and does not automatically mean a child needs antibiotics. That decision should be made by your doctor when they see your child. Of course, if there is anything about your child’s activity level, illness or health that concerns you, you should never hesitate to have them evaluated by their doctor.