fever...

A fever is a temporary increase due to illness or disease. A child has a fever if the temperature is at or above one of the following levels:

100.4°F (38°C) measured from the floor (stop) 99.5°F (37.5°C) measured from the 'mouth (mouth)

Fever A higher than normal temperature. It usually means that there is a pathological process in the body. Exercise, hot weather, and regular childhood vaccinations can also increase body temperature.

What causes fever?
Fever is not a disease in itself. But this is a sign that something is wrong with the body. A fever doesn't tell you what's causing it, or even that it's an illness. It can be bacteria or virus. Or it could be an allergic reaction to food or medicine. Excessive heat from playing or being in the sun can also cause heatstroke.

The best way to check for fever is to use a thermometer.

Digital thermometer (oral, rectal or armpit) (forehead)
The thermometer is the best method for children under 3. For older children and adults, take the position heat under the arm or mouth.

Most thermometers today are digital, but there are some glass thermometers with mercury that still work. Mercury is a toxic substance that is dangerous to people and the environment. Because glass thermometers can be damaged, they must be disposed of in accordance with local, state and federal laws. For information about mercury thermometer disposal, contact your local health, waste disposal or fire department.

Fever is not a disease in itself, but a sign that something is wrong in the body. In children, illness, exercise, hot weather and routine vaccinations can cause high body temperature. Watch for other symptoms besides high fever; for example: red face, warm skin, little urine, loss of appetite, headache or other signs of infection or illness. When you learn that someone has a fever, you can treat them with the dose of acetaminophen or ibuprofen recommended by your healthcare provider. Call your doctor if a baby under 3 months old has a fever or get medical help right away if the fever is accompanied by seizures, fatigue, unusual breathing, stiff neck, confusion, or other signs of serious illness.