There is no single symptom that concerns parents more than the presence of fever in their child. Fever is misunderstood and thought of as harmful to our children. In actuality, fever helps us fight off infection.
Fever is defined as any temperature 100.4 or greater. In order to better understand fever it is important to understand our body's normal temperature control mechanisms.
Humans live in many different climates and therefore we must be able to warm and cool ourselves based on different circumstances. In order to warm our body, our blood can be shunted away from our arms and legs (feeling clammy), and we can contract our muscles vigorously (shivering) to generate heat.
In order to cool our body, we can shunt blood to our arms and legs (feeling hot), breathe rapidly (bringing in 70-degree air and breathing out 98-degree air), and sweat. Our body normally maintains its temperature between 97 and 100.3 degrees.
These normal temperature-regulating abilities work to our advantage when we have an infection. Most bacteria and viruses are most infectious at 97-100 degrees. When infected, our white blood cells can send signals to our brain to raise our temperature to a set point, say 103 degrees, in order to help fight the infection. When this happens our body senses that it is cold and activates our warming mechanisms. Our skin becomes cool and clammy, and we start to shiver.
As we generate heat, our temperature rises until it reaches the new set point. As we pass the set point, say 104 degrees, our body activates its cooling mechanisms. This results in sending blood to your skin, causing it to get warm and red, increasing your heart rate and breathing faster.
As we shed heat, our temperature falls until it crosses our temperature set point, say 102 degrees, reactivating a warming cycle. This is why your daycare called and said your child's temperature was 102, and by the time you got there or to the doctor's office, it was 98.6.
When you are infected it is normal for your temperature to rise and fall around a higher set point. This process is controlled not by the infection but by your body's response to the infection. Height of temperature is limited by physiologic processes and in and of itself generally is not harmful.
Should you have any concerns about your child or his or her temperature you should contact your pediatrician to discuss the symptoms.