
19/08/2025
A fever is a controlled increase in your body's temperature,orchestrated by your immune system and regulated by the brain. It's not the illness itself, but rather a defensive response to it.
What Makes a Fever? đĄď¸
Your body's temperature is regulated by a part of your brain called the hypothalamus, which acts like a thermostat. Normally, it's set to around 37°C (98.6°F).
When your body is invaded by pathogens like bacteria or viruses, your immune cells fight back. In this process, they release chemical messengers into the bloodstream. These messengers travel to the hypothalamus and essentially tell it to turn up the heat. The hypothalamus then releases its own chemicals that raise the thermostatic set-point. Your body now thinks its normal temperature is too cold, so it starts shivering and constricting blood vessels in your skin to generate and conserve heat until it reaches the new, higher set-point.
Chemical Mediators of Fever
The chemical messengers that trigger a fever are called pyrogens (from the Greek pyr âfire," gen "producer"). The most important ones produced by your own body (endogenous pyrogens) are:
Interleukin-1 (IL-1)
Interleukin-6 (IL-6)
Tumor Necrosis Factor-alpha (TNF-Îą)
Interferons (IFNs)
Prostaglandin E2 (PGE2): This is the final key mediator released within the brain that directly acts on the hypothalamus to raise the set-point. Most fever-reducing drugs, like aspirin and ibuprofen, work by blocking the production of prostaglandins.
Pneumonic
"Inflammation Likes To Increase Pain."
Inflammation/Likes: Interleukins (IL-1 and IL-6)
To: Tumor Necrosis Factor-Îą (TNF-Îą)
Increase: Interferons (IFNs)
Pain: Prostaglandins (PGE2)