Eli5: Why do we hurt so much during fever?


Like simple thing like washing hair. Why does each hair folicle have to hurt when cleaning . Or brushing teeth.

In: Biology

during a fever, your immune system is raging against whatever is ailling you.

There’s gonna be a lot of inflammation and with that, an acutely overstimulated nervous system.

Good feelings, well, feel good…

but even a good feeling can get irritating after a while.

Now multiply that by 100, with a bad fever.

When your immune system is actively fighting something, it releases these sort of alarm signal proteins into your blood. Because your blood vessels will be more dilated than normal they can pass through the blood/brain barrier and start binding to things. This isn’t usually dangerous at all, there’s not enough of them for that. But there is enough to completely screw you over emotionally.

You’d be feeling pretty lousy just from your normal immune response even if this didn’t happen. These proteins make it worse by making you react emotionally to the symptoms. Its like how when you get an injury and it hurts more if you keep focusing on it, but gets much more tolerable when your attention is diverted. Only in this case there’s no real way to stop it since its directly affecting your brain.

Knowing this can actually be super helpful though. A lot of times you’ll start to be affected emotionally a day or two before you experience physical symptoms, giving you a bit of warning.