Fever in Adults

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• Fever in Adults Overview
• Fever in Adults Causes
• When to Seek Medical Care
• Exams and Tests
• Fever in Adults Treatment
• Self-Care at Home
• Medical Treatment
• Next Steps
• Follow-up
• Prevention
• Outlook
• Synonyms and Keywords
• Authors and Editors

Fever in Adults Overview

A fever is higher-than-normal body temperature. It is a symptom caused by a variety of illnesses.

Every one of us has experienced the wave of chills and exhaustion that a fever causes. Fever usually occurs in response to an infection or inflammation. However, many other causes are possible, including drugs, poisons, cancer, heat exposure, injuries or abnormalities to the brain, or disease of the endocrine (hormonal) system.

A fever rarely comes without other symptoms. It is often accompanied by specific complaints, which may help to identify the illness causing the fever. This can help the doctor determine which treatment is necessary.

• Normal body temperature can vary depending on the individual, the time of day, and even the weather. For most people, a temperature of 98.6°F is baseline.
  
  
• Temperature is usually controlled by the part of the brain called the hypothalamus. The hypothalamus is like a thermostat for the body. It maintains normal temperature through heating mechanisms, such as shivering and metabolism, and cooling mechanisms, such as sweating and dilating (opening) blood vessels close to the skin.
  
  
• Fever occurs when the body’s immune response is triggered by pyrogens (fever-producing substances). Pyrogens usually come from a source outside the body and, in turn, stimulate the production of pyrogens inside the body. Pyrogens tell the hypothalamus to increase the temperature set point. In response, our body begins to shiver; our blood vessels constrict (close); we get under the covers in an attempt to reach the new temperature that is higher than our baseline.
  
  
  • Pyrogens (fever-producing substances) that occur outside the body
    
    
    • Viruses
      
      
    • Bacteria
      
      
    • Fungi
      
      
    • Drugs
      
      
    • Toxins