I see you cited environmental allergies, which means airborne pollen or fungal spores etc. Personally, while I generally avoid medications, and hate the drowsiness from Benadryl (and the dementia), Allegra works great for me. Lasts about a day, is very effective, and there are no noticeable side effects.

I also have food allergies. For that, I read labels, and ask questions at restaurants. I'm allergic to tree nuts (pecans, almonds, cashews, basically everything called a nut that isn't a peanut) but not peanuts. Thankfully most dishes which have tree nuts tend to call them out in the title or description. Allergens from a list of 8 (9?) are required to be bolded or listed as an allergen in the US for packaged foods. I pay attention to "may contain" or "produced on equipment/in a facility that..." warnings, but note that in the US, those are optional.