Fever, also known as pyrexia, is a condition of elevated body temperature, which usually occurs as a concomitant defense against invading living microorganisms or other recognized as foreign substances, as well as rarely occurring in the context of other inflammatory processes, trauma or as a concomitant in some tumors. Fever is to be distinguished from the elevated temperature.

What is fever?

A fever is an increase in body temperature. Fever is said to be in humans when it exceeds its normal temperature, which is between 36 ° C and 37.9 ° C.

A fever is an increase in body temperature. Fever is said to be in humans when it exceeds its normal temperature, which is between 36 ° C and 37.9 ° C. From 38 ° C it is called a slight fever, the state becomes dangerous when the temperature exceeds 40 ° C. Fever does not just manifest itself - the patient feels cut off and sick the higher his body temperature rises. He often sweats and can suffer from other side effects.

The processes involved are based on complex physiological reactions, including, among others, a controlled and limited increase in body temperature actively induced by the organism. The latter arises as a result of a temperature setpoint change in the hypothalamic thermoregulation center. Fever is thus an example of a regulated change in homeostasis.

Contrary to a common misconception, fever is not the cause of illness in most cases, but part of the organism's response to disease. Accordingly, it is indeed a common practice to reduce fever above a certain level symptomatically to avert alleged harm to the patient; However, this frequent practice often does not correspond to the state of research in fever physiology. Instead of routinely reducing the temperature of the fever above a certain temperature, symptomatic therapy should be guided by the condition and secondary risks of the fever in certain groups of patients.


Fever is an immune reaction of the body of identical organisms, which includes all mammals and therefore also humans. They respond to the invasion of living foreign bodies and try in this way to kill them. The working principle is simple: fever attacks the enzymes that belong to the group of proteins. These are required for metabolic processes and many other important processes in the body of all living things.

However, they can survive only at certain temperatures, otherwise they are destroyed irreversibly - this temperature optimum is different for each living thing. The so-called denaturation of the enzymes is reflected, for example, in fried eggs: when heated, the proteins turn white and do not return to their original state. If this happens in the living being, it dies - in this way the body kills bacteria among other things.

In the case of injuries or open wounds, the body often raises the temperature in the appropriate area in a preventative manner. In this way, it should be prevented that invading bacteria find a pleasant habitat there. Even with bruises or other injuries, the body can react with fever. Some tumors also trigger fever in the body. The fever arises in these cases through complex chains of reactions and does not always occur. It is usually accompanied by other symptoms, which are also caused by the new formation.

Diseases with this symptom

  • cold
  • Meningitis
  • Dreitagefieber
  • Angina tonsillaris
  • flu
  • lung infection
  • measles
  • Scarlet fever
  • abdominal influenza
  • Bacterial infection
  • tuberculosis
  • Non-Hodgkin lymphoma
  • Otitis
  • appendicitis
  • thyroiditis
  • ankylosing spondylitis
  • Systemic lupus erythematosus
  • blood poisoning

Diagnosis & History

If there is a suspicion of fever, it can be diagnosed either by a doctor or the person concerned or a relative / acquaintance by measuring the body temperature.

This is done with the help of a fever thermometer, which is usually put under the armpits or in the anus. As early as 37.6 ° C doctors speak of an elevated temperature. In addition, the doctor will ask for accompanying symptoms - for example, coughing or headache and body aches occur in a flu-like infection. Blood and stool examinations to determine inflammatory findings complete the diagnosis.

Since different types of fever exist, it is not possible to speak of the course. However, the respective curves show that those ascents and descents have. The former are often fast, while the sinking is slower. Peak values ​​can be observed at specific, always identical times (for example, always at noon or in the evening).


  • cold
  • bronchitis
  • Angina tonsillaris
  • flu
  • Scarlet fever
  • measles
  • rubella
  • chickenpox
  • typhus
  • syphilis
  • abdominal influenza
  • Pfeiffer's glandular fever
  • yellow fever
  • typhus fever

When should you go to the doctor?

Fever is a clear sign of illness for many people. Others wonder to what extent fever is actually a reason to visit a doctor. Body temperature values ​​between 38 ° C and 39 ° C are considered a moderate fever, the measured values ​​above as a high fever.

Anyone who feels reasonably good despite moderate fever and also does not suffer from any chronic illness often gets along with home remedies and does not need a doctor. With a body temperature of 39 ° C upwards a visit to a doctor is advisable. Chronically ill, pregnant women, infants and toddlers should definitely consult a doctor at the latest in case of high fever.

Fever is not to be considered solely as a symptom of cold or other infections. Fever can be one of many symptoms of a potentially life-threatening illness, such as cancer. In the case of globetrotters, a fever that occurs after the return of the animal is always thought to be associated with a tropical disease such as malaria. Rheumatism and other autoimmune diseases also often cause fever.

The treatment of the fever by a doctor is smarter, especially in high fever, than to endure the fever alone. An experienced physician knows when a fever under his control contributes to the healing process and when he prescribes better means of reducing fever. In addition, fever gradually weakens the body gradually and a visit to the doctor in addition to the fever struggles.

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Treatment & Therapy

Home remedies F for fever Regardless of the cause, fever is first treated with antipyretic drugs to reduce the fever. Known agents are, for example, acetaminophen or ibuprofen. If the cause of the fever can be treated medically, it is an unwanted, unnecessary reaction that puts people at risk. If his body temperature rises above 40 ° C, his own enzymes denature and he kills himself with the fever.

If fever occurs in response to bacterial ingress, antibiotics are used. These are administered for example in the form of tablets or applied as an ointment to wounds. Even viruses can cause fever, for example, the flu. In this case, a neuraminidase inhibitor is administered, which prevents the viruses from spreading further.

In fever, the fluid requirement is increased, so here is to pay particular attention to a sufficient hydration. In the first phase, in which chills are often felt, heat loss of the body should be avoided. Cooling measures are useful at extremely high temperatures, then z. As ice pack placed in the last.

Physical protection, so avoiding physical and mental overstraining, is recommended. Fever above 40 ° C must be treated by antipyretic therapy. Especially children and the elderly are sensitive to high fever. In young children, febrile convulsions can occur especially after a rapid increase in fever.

Outlook & Forecast

In case of fever, the patient usually does not need to go to a hospital and even in rare cases to a doctor. Fever is always triggered when the body fights against a virus or an infection and is usually the forerunner of a cold and a flu.

Those who suffer from fever should give the body above all a lot of rest and relaxation. By rest, the immune system can regenerate again. In most cases, the fever falls in the patient after a few hours or at most after a few days.

With a fever, the person should never go to work and avoid other physical activities, because the body is strained, which slows down the healing process. If the fever is relatively high, you can also take medicines to relieve the fever. These include above all analgesics, which can also reduce the fever.

With a very high and long-lasting fever, a doctor must be consulted in any case. In this case, the fever could be linked to a worse infection. In most cases, however, fever is quite harmless and can be treated relatively well by domestic means and bed rest. For the complete regeneration one week should be planned.


Fever caused by infection is the only form that can be effectively prevented. For example, you can protect yourself from colds by wearing warm clothes, and you can get vaccinated against the flu. If you get sick, it's important to take care - and you should also see the doctor to have the disease treated in time.

For open wounds, hygiene is the top priority for preventing fever. The wound must be cleaned, disinfected and germ-free according to the doctor's instructions. Preventive fever of the body can be treated with antipyretic drugs, but should seek the advice of the doctor.

You can do that yourself

Fever usually occurs when the body has to defend itself against a virus or other invader in the body and for it must raise the body temperature. Therefore, fever is always a sign of infection, a flu or just a cold. Most of the time, the fever disappears on its own without the patient having to do anything about it.

It is important to provide the body with peace and opportunity for recovery. Bed rest speeds healing. If the fever is high, the patient can also help with medication. Here, antipyretic drugs can be effective. However, they should be taken only to a small extent, as they are relatively difficult to digest for the stomach. A doctor needs to be visited only when the fever is extremely high and does not disappear by itself. It is important that the patient drinks a lot of water in case of an infection.

In the case of an infection with certain foods, only water and a meager diet should be consumed to protect the stomach. To keep an eye on the fever, it is advisable to use a clinical thermometer. This is available in every pharmacy and gives relatively reliable values ​​about your own body temperature.

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