Causes of fever

Synonyms

med .: Hyperthermia, English: fever

introduction

One speaks of a fever when the body temperature exceeds the normal value of 37 degrees Celsius. A distinction is made between different types of fever.

A temperature below 38.5 degrees Celsius would be described as a preliminary stage of the fever and thus subfebrile.A real fever (febrile) is when the temperature reaches 38.5 degrees Celsius. The temperature can be measured most precisely in the ear or rectally.

Fever is always to be understood as an expression of an inflammatory reaction of the body! It can therefore have various causes, which are explained below.

Overview for the causes of fever

In order to find out the cause of your fever better, this classification serves as a simplified (!) Overview:

Classification according to temperature rise:

Fever below 38.5: viral diseases, cold
Fever over 38 degrees with temperature fluctuations: blood poisoning
Fever over 38.5: bacterial diseases, flu

Classification according to temperature profile:

continuous fever: more bacterial
bimodal course, especially Sharp rise in temperature in the morning and in the evening: more viral
Wavy rises and falls: This could be due to brucellosis or Hodgkin disease.
Read more about this at: Brucellosis, Hodgkin disease
Fever with no fever: have you been to the tropics before? In Africa? Your fever could be caused by life-threatening malaria.
Read more about this at: malaria

What are your accompanying symptoms? Chills, shortness of breath, cough, painful urination?
If you only have a fever without any other accompanying symptoms, then you have come to the right place: Fever with no other symptoms

Flu or cold as a cause of fever

Flu as a cause of fever

A high fever is a typical symptom of the flu. As a result of an infection with influenza viruses, in addition to the fever, chills, a pronounced feeling of weakness and fatigue occur. Typically, the fever occurs very suddenly and is above 39 ° Celsius. The fever usually lasts for several days, but after a week the patients are usually free of fever again.

Could the flu be behind your fever? Read also: Flu symptoms

Cold as a cause of fever

A cold can cause a fever. The immune system tries to fight the infection through a defense reaction and releases substances that increase the body's setpoint temperature. The result is fever and chills. With a cold, however, there is only a slight increase in body temperature up to a maximum of 38.5 ° Celsius. A high fever above 39 ° C is more likely to suggest flu.

Also read: Symptoms of a cold

Bacterial diseases as a cause of fever

Bacterial diseases are sometimes accompanied by a very high fever over 38.5 ° Celsius. If left untreated, the symptoms usually do not improve, which is why treatment with antibiotic drugs must be used. After antibiotics, the fever drops rapidly and the symptoms improve. Examples of bacterial diseases that cause a fever include pneumonia (pneumonia), whooping cough (especially in children), scarlet fever (especially in children) or salmonella poisoning.

Find out more about bacterial diseases that can trigger a fever at:

Symptoms of whooping cough
Symptoms of Scarlet Fever

Tonsillitis as a cause of fever

With a purulent tonsillitis (angina), in addition to the severe sore throat, in many cases there is also a sudden, high fever and chills. In most cases, acute tonsillitis is caused by the bacterium staphylococcus. After about a week the fever will gradually subside. However, it takes up to two weeks for the tonsils to swell completely again and for the disease to be over.

Would you like to learn more about this topic? To do this, read our next article below: Symptoms of tonsillitis

Pneumonia as a cause of fever

Typically, pneumonia is caused by bacteria (e.g. pneumococci or streptococci). Pneumonia is a serious illness that must be treated with antibiotics, otherwise there is no improvement. The patients have a severe cough and spit out yellow-greenish sputum. Another characteristic symptom of pneumonia is the sometimes very high fever, which can be more than 40 ° Celsius and is accompanied by chills, hallucinations and confusion.

Do you suspect you may have pneumonia? For detailed information on the most common signs of pneumonia, see: How do I recognize pneumonia?

Cystitis as a cause of fever

Inflammation of the bladder (cystitis) is caused by bacteria that rise up through the ureter into the bladder and cause inflammation in the lining of the bladder wall. As a result, the inflammation levels in the blood rise and the immune system is activated. Sometimes a cystitis can lead to a mild fever. This is a sign that the inflammation is more severe and that a doctor should be seen. With antibiotic therapy, the cystitis can usually be dealt with quickly and the fever disappears.

Could you have a cystitis? Then be sure to read our page: Cystitis

Prostatitis as a cause of fever

Acute inflammation of the prostate (prostatitis) in men is caused by bacteria such as Escherichia coli. In addition to problems and pain when urinating, those affected suffer from a high fever and a very pronounced feeling of illness. Body temperature can rise to over 39 ° Celsius and is accompanied by chills. Prostatitis must be treated with antibiotics as quickly as possible, otherwise there is a risk of chronic prostatitis.

Further information on this topic can be found at: Inflammation of the prostate (prostatitis)

Viral diseases as a cause of fever

Fever is a frequent accompanying symptom in viral diseases, with the body temperature only rising slightly to a maximum of 38.5 ° Celsius. Viral infections typically cause illnesses such as sore throats, runny nose or gastrointestinal infections (gastroenteritis). The majority of colds and most childhood illnesses are caused by viral infections. Very high fever rarely occurs in viral diseases. An exception is three-day fever (Exanthema subitum). This is a childhood disease caused by herpes viruses. In addition to the increased body temperature, there are no other symptoms and the fever usually subsides after three days.

You can find more information on this topic at: Virus infection - everything at a glance

Bronchitis as a cause of fever

Acute bronchitis is an infection of the bronchi, which in the majority of cases is caused by viruses. Those affected suffer from severe coughing and difficulty breathing. In addition, there can also be an increase in body temperature and fever, whereby the temperature usually does not rise above 38.5 ° Celsius. In rare cases, bronchitis is bacterial, which can lead to a very high fever of over 39 ° Celsius.

Blood poisoning as a cause of fever

A high fever over 38 ° Celsius is a characteristic feature of blood poisoning (sepsis). Bacteria entering the bloodstream lead to a systemic inflammatory response in the body. As a result, the immune cells release pyrogens, i.e. substances that cause fever, and the body temperature rises. Typically, the fever comes on very suddenly, goes down, and then rises again. This process is known as remitting fever. The episodes of fever in blood poisoning are accompanied by severe chills, confusion, and faster breathing. In the case of a high fever and suspicion of blood poisoning, the patient must be taken to a hospital as quickly as possible, otherwise organ failure and death can occur within a very short time.

Are you concerned that blood poisoning could be causing your fever? Then be sure to read our page: This is how you can recognize blood poisoning!

Infected wound as a cause of fever

An infected wound that has not received adequate care can lead to a fever. A high fever and chills are clear alarm signals. There is a risk that the bacteria have spread out of the wound and entered the bloodstream. In the case of so-called blood poisoning (sepsis), the bacteria can then reach all organs via the blood and cause serious complications.
Even small wounds, e.g. a scratch on the arm or an inflammation of the nail bed can become seriously infected and cause a fever and sepsis. However, this only happens in rare cases. Nevertheless, even small wounds should be treated properly!

Do you have a wound and a fever? Then you should definitely get clarified whether a dangerous blood poisoning could be behind your fever! We recommend our website to: Symptoms of blood poisoning

Abscess as the cause of your fever

An abscess is an encapsulated focus of inflammation with a collection of pus that is triggered by a bacterial infection. The abscess cavity is separated from the rest of the tissue by a covering made of connective tissue, which prevents pus and bacteria from spreading in the body. If the abscess bursts or is improperly expressed, the bacteria from the cavity can spread throughout the body. Those affected suddenly get a high fever, chills and feel very sick.

Not sure if you have an abscess causing your fever? Then we recommend our website for further information: Abscess - Symptoms and Therapy

Vaccination as a cause of fever

Did you or your baby have a vaccination and now has a fever? A fever can occur even after vaccinations. However, this is a normal and usually harmless reaction to the vaccine

Read more on the topic: Fever in adults after vaccination (including fever in babies after vaccinations)

Common causes of fever in baby

Any infection causes a fever in babies relatively quickly.
This is a protective reaction of the body. The increased body temperature is supposed to stop the multiplication of pathogens, and it also activates the immune system.
However, a high fever above 39 ° Celsius means that certain proteins in the body, the enzymes, can no longer work properly and important body functions are impaired.

In addition to infection, there are a number of other causes that can cause a fever in babies. The body's own temperature regulation is not yet fully developed in babies. For this reason, it is difficult for them to adapt to rising outside temperatures and the body reacts with a fever.
Therefore, parents must be careful not to expose their babies to high temperatures, such as direct sunlight, blankets that are too warm when sleeping or high ambient temperatures.

Would you like more detailed information on this topic? Do you want to know how to lower your baby's fever? Or when it can get dangerous? Then you should definitely read our main page about: Fever in the baby - everything about the topic!

Common causes of fever in young children

Young children are much more likely to have a fever than adults. This is completely normal and nothing to worry about. Frequent fevers in young children come from the fact that, unlike adults, children do not yet have a fully developed immune system. Therefore, even minor infections and common colds quickly lead to a high fever.

Common causes of fever in toddlers are often classic childhood diseases. These are infectious diseases such as scarlet fever, mumps, chicken pox, measles or rubella. Most people become infected with the pathogens that cause these diseases as early as childhood and once the infection has healed they usually have lifelong immunity, which means that they do not develop the same disease a second time. Nowadays there is an effective vaccination against most childhood diseases that the pediatrician can give in the first few months of life. Fever is also a common symptom of sore throats, otitis media, or respiratory infections that small children often suffer from.

Find out more about this topic, including when it can be dangerous for your child and how you can lower your child's fever. We recommend our website to: Fever in the toddler

Causes of fever with temperature fluctuations

If you are never free of fever, but your body temperature fluctuates by up to 2 ° Celsius during the day, then this is also referred to in medicine as a remitting fever. Typically, the temperature is lower in the morning after you wake up and peaks in the evening. The causes can be varied, for example remitting fever occurs with the flu or blood poisoning (sepsis). An infection with bacteria or viruses often leads to a remitting fever.

Causes of fever with no fever

Have you been to the tropics? In Africa? And now have a fever?

If you are free of fever for 1-2 days, you must always suspect malaria. If it is a day of complete freedom from fever, this speaks for a Malaria tertiana, if you are free from fever for 2 days, one could Quartana malaria behind it.

The dreaded malaria tropica does not show a typical fever and is mostly characterized by an irregular spread of fever.

Other tropical diseases can also lead to fever; this should be taken into account if you have stayed in a risk area. A high fever is also a symptom of the deadly disease Ebola. Read more about Ebola.

Malaria and Ebola are life-threatening infectious diseases. If you have the slightest suspicion of infection, you should see a doctor immediately. For more information, see: Malaria, Ebola

Measure fever correctly

The temperature can be measured most precisely in the ear or rectally

Read more on the topic: Measure a fever

How does a fever develop?

The mechanism by which fever develops is very complex and should only be presented here in a simplified manner.
In a region of the brain called the hypothalamus, there are nerves that are about 30% sensitive to heat; one part is insensitive to temperature and one part is sensitive to cold. All nerves are in contact with each other and thus set the normal value for body temperature. So-called pyogens can disturb this equilibrium, resulting in an increase in temperature.

If there is a rise in temperature, the heat-sensitive nerves fire faster and there is a further rise in temperature.
Pyogens are fever-promoting substances or substances of the most varied kinds. Foreign bodies and externally supplied pathogens (Viruses, bacteria, particles) as well as substances produced in the body (various inflammatory messengers that are released by the body in the event of inflammation) are pyogens. If these substances are released, various biochemical intermediate steps lead to an increase in body temperature (fever).