• A fever is when the body temperature is above 38.0 degrees
  • There are several causes of fever
  • In the case of unexplained fever, there is at least six weeks of fever without a clear explanation




A fever is when the body temperature is above 38.0 degrees. This must have been measured several times with a good measuring device, otherwise there can be no talk of a fever. The most reliable measuring device is a buttock thermometer. The height of the fever says nothing about the severity of the disease.


Symptoms of fever are feeling very hot and/or cold. You can also experience chills or sweat a lot. Heavy fevers might also trigger a delirious state (losing sense of reality). Sometimes there can be dehydration due to excessive sweating.


Fever is often caused by a virus or bacteria. Fever is a sign that your body is clearing the viruses and bacteria. In that prospect, fever is a good and healthy reaction of the body.
But fever can also signal more serious conditions like cancer, autoimmune diseases, allergic reactions and certain hormone disorders. You can also get feverish from certain medication.

Sometimes no good explanation for the fever is found. We then call it unexplained fever.

HIV and fever

Unexplained fever can be a sign of HIV. Other research into more common causes of fever in patients in the Netherlands has provided insufficient explanation. The fever must be present for about six weeks before you can speak of an unexplained fever. If you are not sure whether you have an unexplained fever, you can contact your doctor.
HIV indicator conditions are conditions or symptoms that occur more often in people with an underlying HIV infection than in people without an HIV infection. Unexplained fever is one of the HIV indicator conditions. If you have or have had unexplained fever and have not been tested for HIV, it is advisable to ask your doctor or general practitioner for an HIV test. Find it difficult to ask for an HIV test? You may download a call card that will help you formulate your question.