Well, my brother's serious respiratory troubles were not so sudden that they came on like an attack, like some dramatic movie thing, he is just an idiot who thought his worsening state would somehow get better on its own, so he waited for hours and it just got worse and worse until it was a real emergency.

So far my only bad reactions have been to mosquito bites, which swell really badly for me though not with respiratory issues. But there might be a family sensitivity because my younger niece actually reacts even worse to mosquitoes, and also to wasps (I've never been stung by one so I don't know whether I'm sensitive), and with the latter she had actually needed an emergency room for her reaction. So yeah, I am wary of my insect reactions too. Mostly I try to avoid any bites with insect screens and using repellants.