Fever is a higher-than-normal body temperature. Normal temperature is usually defined as 98.6 degrees Fahrenheit (F) or 37 degrees Celsius (C). Many healthcare providers would say a person truly has a fever when their temperature is greater than 99.5 degrees F or 37.5 degrees C.

What is going on in the body?

Normal body temperature changes during the day. Exercise, stress , or dehydration may cause a person's temperature to go up. In these cases, it is not considered a true fever. Fever is a symptom, not a disease. A fever may mean that there is something else going on in the body that is causing it. Fever helps the body fight infections by making the body's defense systems work more efficiently. Bacteria and viruses cannot live at higher temperatures and so are killed by fever.

What are the causes and risks of the condition?

Fever can be caused by many conditions, including: infections such as strep throat caused by group A strep , pneumonia , flu and chickenpox tissue injuriestumors or cancer diseases that cause inflammation, such as rheumatoid arthritis medicationsbeing in a hot environment for too long The main risk of mild or moderate fevers is dehydration . People need more fluids than usual when they have a fever. A fever greater than 106 degrees Fahrenheit can result in brain damage and death in some cases. This level of fever is very unusual. It is not usually brought on by common illnesses. Fever in children presents special concerns for parents, since some children have febrile seizures with fever. These can lead to injury to the child, but this is rare.