Fever in children: When to worry You should reach out to your pediatrician if your child 6 months to 2 years: Has a fever higher than 102 F for more than 1 day. Has other symptoms, such as a cough. Get the facts on severe fever treatment (in children and adults) and symptoms. Learn about causes of fever, home remedies to bring it down, ways to prevent it, and find out when to call a doctor. A fever, also known as a high temperature or high fever, is when your body temperature temporarily rises above 38°C (100.4°F). Fever itself is not an illness and is usually a symptom of an underlying condition, such as an infection. This leaflet explains the what causes a fever, signs you have a fever, and when you should see a doctor. Fever symptoms may include more than just an increase in body temperature. In adults and children, a temperature of 100.4F (38C) or higher marks a fever. In babies, a temperature of 99.5F (37.5C. A fever is when your body temperature is higher than your normal average temp. Learn how to take temperature, fever types, symptoms, causes, and treatments. A fever is when your body temperature rises higher than normal. Learn more about fevers including what providers consider a real fever. A fever is a temporary rise in body temperature. It's one part of an overall response from the body's immune system. A fever is usually caused by an infection. For most children and adults, a fever may be uncomfortable. But it usually isn't a cause for concern. For infants, however, even a low fever may mean there's a serious infection. Fever or pyrexia in humans is a symptom of an anti-infection defense mechanism that appears with body temperature exceeding the normal range caused by an increase in the body's temperature set point in the hypothalamus. [4][5][6][12] There is no single agreed-upon upper limit for normal temperature: sources use values ranging between 37.2 and 38.3 °C (99.0 and 100.9 °F) in humans. [1][6][7. A person has a fever when their temperature is higher than 100°F (38°C). Learn about fever types, symptoms, causes, and treatments in this article. A fever is the body's way of battling an illness. Here's how to tell if you have a fever, plus what you should do and when you should seek help.