Welcome to the forum, cindykite.
Do you have "true" allergies? Throat closing, rash, or tingling in your mouth? For those I would see an allergist and not fool around with alternative treatment.
You can find a lot of your own allergies and sensitivities by just keeping a food journal (see many posts with detail in the search box at the top of the page). When you have a good list of your allergens you can google them with the words food allergies and see if there is any relationship between them. I did this and found all my particular allergens are related by one chemical - BUT my sensitivities are a bit unusual and I don't want everyone to think they have the same problem as I have.
With "just sensitivities" there is no treatment except avoidance. I don't get any relief with antihistamines or allergy shots for mine. I DO get very good relief with my tree pollen, grass, dust and mold allergies ("true allergies") from shots.
My sensitivity trigger foods include corn starch, corn syrup, gelatin, dried or canned potatoes, onions, garlic, maple syrup, vaccines, condiments with vinegar, pork, brown sugar, and a whole lot more. I'm fine with corn and potatoes and rice vinegar. It's the processing.
Jaminhealth mentioned Pycnogenol, which I'd not heard of, so I looked it up, and it might help birch allergies. www.nlm.nih.gov/medlineplus/druginfo/natural/1019.html