[ajuc]

Counter-anegdote. I grew up in the countryside, I am allergic to hay, pollen, dust mites, cat and horse saliva, and more.

I moved to a big city when I was ~20 and my symptoms got better, but I'm still allergic to all that - it's simply not putting me in hospital anymore.

Doctors told me most people grew out of the worst symptoms over time.

BTW I also somehow got allergic to kiwi fruits between primary school and my late 20s. I ate them rarely and at one point I found out they make me throat swell like a balloon. Didnt' happened before.