A trademark influenza symptom, the fever—and its characteristics—are distinct.
A fever is the body’s elevation in temperature from its normal state, indicating that something is wrong. The indication may be something as minor as allergies, or teething in small children. Fever may also occur due to infection of all severities and, in some cases, can indicate a potentially life-threatening issue. Don’t think that just because it’s a low fever that nothing is wrong. The Mayo Clinic explains, “The degree of fever doesn’t necessarily indicate the seriousness of the underlying condition. A minor illness may cause a high fever, and a more serious illness may cause a low fever.” Watch for visible symptoms, and when in doubt, use a medical thermometer to confirm the presence of fever.
Symptoms. A fever will often be accompanied by a flushed appearance, possibly sweating and a temperature elevated above your normal body temperature. The average normal body temperature is 98.6 F, but that may vary by as much as a degree. Most consider about 100 F to be a cause for concern, though any persistent temperature elevation may indicate a problem. Depending on the causes, a fever may also be accompanied by nausea, muscle aches, dizziness, weakness, a loss of appetite, diarrhea and a persistent thirst.
Diagnosis. In most cases, a fever will be diagnosed by a physical examination to confirm the presence of symptoms. Many doctors will treat with a broad-spectrum antiviral or antibiotic medication, though something more specific will likely be used if the cause is known or strongly suspected. Blood tests can indicate the presence of a virus or other infectious agent, and mouth swabs can be used to confirm viruses such as influenza. However, during known flu outbreaks, cases with flu-like symptoms are often treated like the flu without an official test.
Causes. Possibly the most common cause of fever is a viral infection, such as the fever associated with flu and some types of cold. Bacterial and fungal infections often cause fever, even in a relatively minor infection. However, some of these infections can be internal, and fever may be the only indicator of their presence. If you have an unexplained fever that lasts for more than 24 hours, especially if it’s accompanied by chills, then it is important to seek medical attention. A fever accompanied by profuse sweating, hallucinations and other serious symptoms is an emergency and must be addressed by a qualified health care provider immediately.