Fever is not an illness in itself, but a sensible defence reaction of the body: the elevated temperature helps the immune system deal with pathogens. In the vast majority of cases, it is caused by a harmless infection that clears up on its own. Often, more important than the exact number of degrees is how you feel overall and how long the fever lasts.
Possible causes
Viral infections
By far the most common cause: common cold, flu, or gastrointestinal infections. The fever accompanies the infection and disappears once it has resolved.
Bacterial infections
Such as tonsillitis, bladder infection, or pneumonia. Here the fever often persists longer or occurs together with localized symptoms and may require targeted treatment.
After vaccinations or with inflammations
A temporary slight temperature elevation after a vaccination is normal. Other inflammatory processes in the body can also trigger fever.
Persistent fever without clear cause
If the temperature remains elevated for an extended period without a recognizable infection, a targeted medical investigation of the possible underlying causes is worthwhile.
Typical steps at the doctor's office
- 1The doctor will ask how long the fever has been present, how high it rises, and what accompanying symptoms you have, and will gain an impression of your general condition through a physical examination.
- 2Depending on the suspected cause, simple additional examinations may be added, such as looking at the throat and ears, listening to the lungs, or conducting a urine or blood test.
- 3Further treatment depends on the cause: in the case of a viral infection, rest and patience are usually sufficient; in the case of a bacterial trigger, a targeted approach is taken.
What you can do yourself
- Give yourself rest and take it easy as long as the fever persists — your body needs the energy for its defense.
- Drink sufficient fluids, as more fluid is lost when temperature is elevated.
- Choose light clothing and a cool environment, rather than bundling yourself up further.
- Monitor the course and your general condition throughout the day; this often tells you more than the temperature reading alone.
A visit to the doctor is advisable if the fever lasts longer than three days, rises above 39.5 degrees, keeps recurring, or is accompanied by a marked feeling of illness. After travel to the tropics, fever must always be checked promptly (malaria). Call 144 immediately for fever accompanied by neck stiffness, severe headache, confusion, shortness of breath, or red skin spots that do not fade under pressure. Even if you are uncertain or have an underlying condition, the family doctor is the right first point of contact.
Frequently asked questions
- At what temperature does one speak of fever?
- Usually a body temperature of about 38 degrees or above is considered fever; below that, one speaks of elevated temperature. However, the number alone is not decisive, but rather how you feel overall and how long the temperature remains elevated.
- Do I always have to reduce fever?
- Not necessarily. Fever is a sensible defense response and does not need to be suppressed at every elevation. Whether measures to provide relief are advisable depends primarily on how much you feel impaired.
- How long may fever last?
- Fever caused by an infection usually subsides within a few days. If it persists longer or your condition worsens, a medical assessment is advisable.
Not sure whether you should go or whom to see? Describe your symptoms — we'll find the right practice in your area.