Never explored the issue of allergies.
When Zhang Shuwen first went abroad, he found it pretentious how people around him treated allergies like a dangerous beast. After all, with Zhang Shuwen's understanding back then, except for drug allergies which were dangerous, he really didn't think allergies to things in daily life were a big deal.
But after truly witnessing someone nearby go into anaphylactic shock from an allergy to some exotic pollen and get rushed to the ICU, he realized it wasn't pretentious; it was due to their physical constitution.
Who the hell would have thought they had no symptoms of pollen allergies normally, but just because they encountered a flower they'd never seen before, which they found beautiful and sniffed a few times, they would go into shock within minutes...
Since that time, Zhang Shuwen has shown respect and best wishes towards the word 'allergy', but never discussed it.
