Anecdotally, I grew up in the land of hand sanitizers and abundant soap, playing in mud, weeding the garden, and catching bugs. I had allergy shots until my teens, and I often still feel like I have a permanent minor cold, which gets better or worse, depending on what's blooming. Moving from Michigan to north Florida seems to have made it worse.
Same as you, I grew up in MI. Moved to Phoenix and my allergies cleared up. About 5 years later, I had seasonal allergies again and they seemed to be worse than ever.
I grew up playing outside all hours of the day/night, every season in Michigan. Rarely hand washing before eating and that kind of stuff. I never had issues with allergies.
I've lived in Boston and Seattle, no issues. Now I live in Dallas (again) and allergy season is not good. Pretty much a guaranteed sinus infection twice a year.
Similar story here - Home is in eastern NC, terrible allergy area, tons of pine trees and moisture) - but mostly places I visit I feel better, and then feel substantially worse when I return home.
