What can cause a fruit and nut allergy?

I've been allergic to apples and that basic species of fruit since I was two. First it started out with only being allergic to the skin and then, to the entire apple itself.

Now, it seems to be starting to happen with Strawberries.

It's not every time that my throat starts to itch like made and swallowing causes the 'I have knife in my throat' sensation.

It really depends on how many strawberries I eat.

It's the same way with nuts, too. Lol.

I can't eat walnuts or peacans. But any other nut is perfectly alright.

Anyway.

I'm allergic to pollen. Any pollen you can possibly think of, I'm allergic to.

Could this play a big factor?

Your body, for some reason, is freaking itself out thinking that the things you eat or touch are bad and your immune is going "holy crap! What is this!? This isn't normal!" and then it goes "Kill it kill it!!" and it sends out a bunch of chemicals and cells to destroy a harmless substance.

Allergies are caused by your body overreacting to something.
There isn't much you can do except for avoiding those things.

Being allergic to pollen is different from being allergic to specific fruits.
There are just somethings in those things that your body isn't very fond of.

Also, the more you are exposed to the allergen the worse it gets, because now your body has 'memorized' the substance and already has a plan on how to attack it if it comes back.

(It's like how some people can see a bug and not be bothered, but some people will freak out and spray it with industrial strength pesticide for 5 minutes.)