Fever does not mean presence of infection. There are many situations where there may be fever without infection. Such fevers do not need antibiotics. 

  • Sepsis, a clinical syndrome, occurs due to the dysregulation of inflammatory response to an infection. The temperature is between 36°C to 38.30°C. Heart rate is often above 90 per minute.
  • Symptomatic inflammatory response syndrome (SIRS)is a clinical syndrome, which occurs as a result of dysregulated inflammatory response to any infections such as inflammation of the pancreas, inflammation of the vessels, clot formations in the veins.
  • Many antibiotics can cause fever; unless they are discontinued, fever will not subside.
  • Hyperthermia, a condition with elevated body temperature, is not called fever. Examples – exposure to heat or heat stroke and in response to anesthetic drugs and anti-psychotic drugs.
  • Hyperthermia may not respond to anti-fever drugs.
  • When fever is more than 41.5°C, it is called acute hyperpyrexia.
  • Hyperpyrexia is often seen in patients with severe infections but it may also occur in brain hemorrhage. It responds to anti-fever drugs.
  • High temperature without infection can be seen in case of a hyperfunctioning thyroid gland.
  • Recreational drugs such as Ecstasy may cause fever without any infection.
  • Mild fever can also occur following exertion.