A fever is a temporary increase in your body temperature, often due to an illness. Having a fever is a sign that something out of the ordinary is going on in your body.
For an adult, a fever may be uncomfortable, but usually isn't a cause for concern unless it reaches 103 F (39.4 C) or higher. For infants and toddlers, a slightly elevated temperature may indicate a serious infection.
Fevers generally go away within a few days. A number of over-the-counter medications lower a fever, but sometimes it's better left untreated. Fever seems to play a key role in helping your body fight off a number of infections.
Causes-- Fever occurs when an area in your brain called the hypothalamus also known as your body's "thermostat" — shifts the set point of your normal body temperature upward. When this happens, you may feel chilled and add layers of clothing or wrap up in a blanket, or you may shiver to generate more body heat, eventually resulting in an elevated body temperature.
Normal body temperature varies throughout the day — it's lower in the morning and higher in the late afternoon and evening. Although most people consider 98.6 F (37 C) normal, your body temperature can vary by a degree or more — from about 97 F (36.1 C) to 99 F (37.2 C) — and still be considered normal. Factors such as your menstrual cycle or heavy exercise can affect your temperature.
Fever or elevated body temperature might be caused by:
· A virus
· A bacterial infection
· Heat exhaustion
· Extreme sunburn
· 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 acellular pertussis (DTaP) or pneumococcal vaccine
Sometimes the cause of a fever can't be identified. If you have a temperature of 101 F (38.3 C) or higher 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.
Symptoms-- You have a fever when your temperature rises above its normal range. What's normal for you may be a little higher or lower than the average normal temperature of 98.6 F (37 C).
Depending on what's causing your fever, additional fever signs and symptoms may include:
· Sweating
· Shivering
· Headache
· Muscle aches
· Loss of appetite
· Dehydration
· General weakness
High fevers between 103 F (39.4 C) and 106 F (41.1 C) may cause:
· Hallucinations
· Confusion
· Irritability
· Convulsions
· Dehydration
Complications- Complications of a fever may include:
· Severe dehydration
· Hallucinations
· Fever-induced seizure (febrile seizure), in a small number of children ages 6 months to 5 years
