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Fever symptoms, causes, treatments

Fever symptoms

A fever is a high temperature when the body's temperature rises above 37.5C (99.5F). The normal body temperature is between 36C-37C (96.8F-98.6F)

The high temperature or fever often lasts around two to three days.

Check for high temperature or fever using an appropriate thermometer and following the instructions.

For adults and children over four weeks old, the NHS recommends an ear or tympanic thermometer, or ones using a special colour changing chemical strip on the skin.

The use of mercury thermometers is no longer recommended because of the risk of breakage.

Cause of fever

A fever isn't a separate illness. Fever or a high temperature is usually a normal response to an infection as the body fights it off. Part of the brain called the hypothalamus may decide to regulate the body's temperature to a higher level.

Common causes of fever are:

  • Colds and flu
  • Gastroenteritis stomach bugs
  • Infections of the ear, lung, skin, throat,  bladder or kidney
  • Inflammatory conditions
  • Side effects of drugs
  • Cancer
  • Routine vaccinations

Other causes of fever include:

  • Blood clot or pulmonary embolism
  • Autoimmune diseases such as lupus, rheumatoid arthritis and inflammatory bowel disease
  • Hormone disorders such as hyperthyroidism
  • Illegal drugs that increase heat production such as amphetamines and cocaine
  • Infections abroad, such as malaria

 

Treating fever

  • Fever usually makes a person feel uncomfortable, and steps may be taken to reduce the fever, by taking age-appropriate medicine, such as paracetamol or ibuprofen, but never aspirin in under-16s.
  • Other home care treatments for fever:
  • Drink eight glasses of water or other clear fluid a day. Iced drinks or ice lollies may have a soothing effect.
  • Wear lightweight clothing and don't use blankets and duvets in bed to avoid getting too warm
  • Make sure the temperature in the room is comfortable and let fresh air in
  • Rest and avoid heavy activity

The NHS does not recommend use of wet sponges to treat a high temperature or fever.

Depending on age, physical condition and the underlying cause of the fever, a person may or may not need to seek medical advice.

Many experts believe that fever is a natural bodily defence against infection. There are also non-infectious causes of fever. These include the temperature related condition  hyperthermia and dangerous rises in body temperature. This may be due to a heat injury, such as heat stroke, or the side effects of some medications.

WebMD Medical Reference

Medically Reviewed by Dr Rob Hicks on May 08, 2013

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