Fever is a body temperature that is higher than normal. A normal temperature can vary from person to person, but it is usually around 98.6°F. It is not a disease. It is usually a sign that your body is trying to fight an illness or infection. Infections cause most fevers. Symptoms: Sweating, Chills and shivering,Headache,Muscle aches,Loss of appetite,Irritability,Dehydration & General weakness. Children between the ages of 6 months and 5 years might experience febrile seizures. About a third of the children who have one febrile seizure will have another one, most commonly within the next 12 months. Causes: A virus, a bacterial infection,heat exhaustion,certain inflammatory conditions such as rheumatoid arthritis — inflammation of the lining of your joints (synovium),a malignant tumor,some medications-such as antibiotics and drugs used to treat high blood pressure or seizures, some immunizations- such as the diphtheria, tetanus and a cellular pertussis (DTaP) or pneumococcal vaccine. Sometimes the cause of a fever can't be identified. If you have a fever for more than three weeks and your doctor isn't able to find the cause after extensive evaluation, the diagnosis may be fever of unknown origin. When to see a doctor: Fevers by themselves may not be a cause for alarm — or a reason to call a doctor. Yet there are some circumstances when you should seek medical advice for your baby, your child or yourself.