I grew up on a farm and was constantly exposed to all kinds of soil, vegetables, animals, trees, well forests, grasses and hay.. and I never had any kind of allergies. However, when I moved to another European country I had severe reactions to the local mosquitoes. Not that it was itching very much or anything, just that it was bleeding like crazy. I would wake up in the morning and look like I had been through an especially messy vampire attack during the night. Bloody forearms, ankles.. It took a year, and then I got used to it and stopped having any reaction whatsoever (same as in my home country). No bumps, no itching.

Then Japan.. and the same happened, with the local mosquitoes. Bleeding like hell. It took slightly longer, but I did get used to that as well, so now there are no problems.

And.. I got itchy eyes when I travelled to Japan. As I said, I've never been allergic to anything. I didn't have sneezes or the like, but it was problematic. I tried to wash my eyes with salty water every day, and I got eye drops.. this went on for several years while I kept visiting Japan (I always stayed for long periods). Last year I finally concluded that it was actually the Sakura trees.. (The Cherry Blossoms) which caused it. And this year the symptoms are close to non-existing, so I'm concluding that I'm getting used to that as well (and I have visited Sugi forests many times over the years too, and no problems there). Hopefully.