Metamizole is the only thing that works for me when I have fever. But it seems that I recently developped an allergy to it, which is a bummer. Every single damn time I take metamizole, I develop very itch rashes. So by taking some substance it seem I became more sensitive to it's side effects, not less.
The immune system is so complex. I have to wonder if allergies develop when something else is stressing the immune system and it misidentifies the culprit.
So my best guess is that when you live a life indoors for years without much exposure to natural outdoor bacteria/viruses/plants, and then you encounter a human disease, your immune system goes into overdrive and misidentifies the culprit.