The temperature of the human body varies based on several factors. Here is a guide to help you recognize a fever and what to do about it.
A fever is not an illness in itself but a symptom of an underlying condition, usually an infection. It is an abnormal spike of the body’s temperature. Fever is a normal defence mechanism. The body has an internal thermostat called the hypothalamus.
This thermostat regulates the production and loss of body heat in order to maintain a normal temperature. When an infection occurs, the thermostat is adjusted upward, which activates heat production. A fever can also be caused by other factors.
A normal body temperature does not correspond to a specific number, but rather to a range of temperatures. It depends on the person, age and area of the body where it is measured. A number of factors, such as physical activity and the time of day can also modify it.
| Body part | Normal temperature range |
|---|---|
| Rectum | 36.6ºC – 38.0ºC (97.9ºF – 100.4ºF) |
| Ear | 35.8ºC – 38.0ºC (96.4ºF – 100.4ºF) |
| Mouth | 35.5ºC – 37.5ºC (95.9ºF – 99.5ºF) |
| Armpit | 34.7ºC – 37.3ºC (94.5ºF – 99.1ºF) |
It can be said that a person has a fever when the temperature that is measured rises above the highest value range. By definition, a fever corresponds to a rectal temperature that is above 38.0 ºC.
When someone has a fever, he/she usually feels discomfort. The manifestations that can accompany it include:
Many children who have a fever, especially young ones, are unable or have difficulty to express their discomfort. An attentive parent will be able to identify the fever by the presence of certain signs, for instance, if the child:
To determine if someone has a fever, it is necessary to measure his/her temperature. Observation of signs and symptoms (as well as estimation, by putting a hand on the forehead) are not sufficient to confirm the presence of fever.
When someone has a fever:
Acetaminophen and ibuprofen are both over-the-counter medications that can be used to bring down a fever.
Acetaminophen is usually the medication of choice for treating a fever, particularly in children. If your child does not tolerate the drug, is allergic to it or it has no effect on the fever, try administering ibuprofen, unless otherwise indicated by a healthcare professional. Acetylsalicylic acid (aspirin) should not be administered to children under the age of 18, since it has been associated with Reye syndrome, a very rare but very dangerous illness.
In children, the dose varies based on weight. Ask your pharmacist to calculate the appropriate dose. Acetaminophen and ibuprofen are available in different formats (drops, syrup, tablets) and concentrations. If your pharmacist recommends medication in liquid format, it is important to carefully measure the dose using an accurate tool (graduated spoon, dosing syringe, etc.).
Regardless of the person’s age, it is advisable to speak to a doctor or pharmacist to assess the situation. It is preferable not to administer or take fever medication without first seeking the advice of a competent professional.
A medical consultation is necessary when the:
Don’t hesitate to speak to your pharmacist if you have any questions about fever.
