Normal body temperature, when measured by an oral thermometer, is between 36.5°C and 37°C. You are said to be suffering from a fever if your body temperature is over 37°C (37.8°C or more when measured rectally).
In an adult, the level of fever generally reflects the severity of the illness causing it. In a child, however, this is not necessarily the case. A child with a mild cold may have a temperature of 40°C, while a child with a serious illness - bacterial pneumonia, for example - may have a temperature lower than that.
In a newborn, the body's temperature control is not yet well developed. As a result, signs other than a fever - poor appetite, lethargy and irritability - may be earlier indicators of an infection and are more helpful than temperature in assessing a newborn's condition.
The function of a fever
In the majority of cases, a fever is the body's natural reaction to an acute viral or bacterial infection and is not necessarily considered a dangerous condition in itself. Rather, a fever is a sign that the body is defending itself against the infectious invader. Since viruses and bacteria do not survive as well in a body with an elevated temperature, fever is actually an ally in fighting infection. An elevated temperature also increases the production of infection-fighting white blood cells and even increases their speed of response and enhances their killing capacity.
A fever can be caused by a wide variety of factors. Dehydration, overexertion, mosquito bites, bee stings, allergic or toxic reactions and viral or bacterial infections are just a few. A fever of unknown origin (FUO) is a condition defined as an elevated temperature lasting for three weeks or more without an identifiable cause.
Paracetamol (found in Panado, Calpol and other over-the-counter medications) is a drug that helps to lower fever. Paracetamol is also an analgesic (pain reliever), so it eases the discomfort and body aches that often accompany fever. It is available in liquid or pill form, as well as in suppository form for infants.
Note: In excessive amounts, this drug can cause liver damage. Be careful not to exceed the correct dosage for your child's age and size.
Ibuprofen (Nurofen and others) is another fever-reducing medication that relieves mild to moderate aches and pains. Be sure to take the medication with food to prevent irritation of the stomach. Ibuprofen is available in liquid or pill form. Follow dosage directions on the product label.
Do notgive aspirin to a child with a fever. Many fevers are caused by viral infections, and the combination of aspirin and viral illness has been linked to the development of Reye's syndrome, a progressive and very dangerous liver disease.
- Administer paracetamol to reduce a fever of 40°C or higher. Do not use/give in higher doses or more frequently than directed.
- It is very important to maintain fluid balance, so drink plenty of water or fruit juices.
- For a temperature of above 40°C, bathe or sponge the skin with lukewarm water (not cold water). Evaporation will have a cooling effect.
- Remain at home and rest.
- Remove extra layers of clothing.
When to call the doctor
- When a newborn has an elevated (or low) temperature.
- If the sufferer is a child under six months of age.
- When the fever is accompanied by a stiff neck, confusion, lack of energy, difficulty in awakening or inconsolability.
- When the sufferer has fever and shows signs of febrile seizures: muscles throughout the entire body stiffen, eyes may roll, your child's head may jerk, hands and/or feet may tap, and loss of bowel and urine control may occur.
Previously reviewed by Prof Helmuth Reuter, University of Stellenbosch and Tygerberg Academic Hospital
Reviewed by Prof E Weinberg, Emeritus Professor of Paediatrics, May 2011