Simple. Don't eat Dairy Products.
Oh you want the back story? That's why you came here?
Sure... no prob, pull up the comfy chair and read a bit.
I grew up a normal-whatever-that-is-kid in South Jersey. That meant that I'd have plenty of milk on my Lucky Charms, more milk with my cookies, a half pint subsidized by the State of New Jersey when I went to my public school, cheese on my ham sandwiches, Mac and Cheese meals and so on.
Philadelphia area has the distinct pleasure of having two Hay Fever Seasons, one in Spring when the flowers are out, and the one I suffered from from Labor Day until the first hard freeze.
By the time I was old enough to realize that this was a normal thing for me but not for others, I was taking a Chlor-Trimeton "elixir" when the allergies acted up, and later a little orange pill twice a day to mask the symptoms. They worked but made me sleepy and cranky for the four months of the Hay Fever Season.
I was trucked into Philadelphia for "Allergy Tests" that told me that I shouldn't eat dozens of things, stay away from dust, and not go outside. Basically live in a bubble.
Those painful allergy shots did nothing. Waste of time, and effort getting needles every week or so all year around.
This went on into my teens when I stopped getting the shots since it was widely understood that they were pretty useless, and continued on with the little orange pills twice a day from late August until Christmas.
Miserable little things that at least tasted sweet.
At one point, over Sunday Dinner we had a conversation. Mom's house was always full of interesting people and this dinner was no exception. The conversation went to my having to excuse myself to take an annoying little pill and my allergies when one of the people there made an interesting comment.
He said that he had gone through what I had but now since he went off of dairy, he had absolutely no problems. I said that since it was July I would consider it, after all I could give up a little milk once in a while.
Going home after that meal, I looked at the Extra Sharp Cheddar that I was fond of, the baked goods and realized that there was more to it than that. Basically the extra allergens that kept me just under having an allergic reaction that were in all that cheese and milk would have to be gone by mid August.
One after another I got rid of the things by drinking, baking, and otherwise eating the dairy products and by Mid August that year the house was clear of Dairy.
Then we waited for the oncoming harvest. Pollen would begin to form in the Midwest, work its way over the Appalachians and find their way into my lungs.
That particular year instead of taking two pills a day, I took three.
Three Individual Pills. On three different days.
That side comment freed me of shots, pills, drops, kleenex and discomfort. I had gone from the kid who had intense asthma and a sickly fall and early winter to being completely clear to the point where I could go out to the tall grasses of Valley Forge National Park and skate through it on a warm weekend in the peak of the pollen.
We were all shocked. It had worked.
The next year I did it again - Zero Allergy Pills. Everyone else was suffering and I was clear. People began to ask and I told them how I did it. Few people believed me but they all listened.
It is now at least 15 years later. I enjoy dairy products now because I live in Florida near the beach. The air here is not the polluted grey that is up in the Northeastern US. Head west of here, you cross over an uninhabited island in the Bahamas and nothing until you hit Western Sahara. No pollution would be an exaggeration but the air here is clean and crisp.
South Florida still has it's own allergy season, but I don't notice it until someone tells me that it's here.
One side benefit. I used to be deathly allergic to cats. I could not walk into a house with a cat, no matter how clean, without leaving 20 minutes later with no voice. Now I can manage around 2 hours, more if the place is clean.
Purging yourself of all of those overloaded allergens by not drinking milk, whole or otherwise, saved me. It may help, it may not. Your Mileage May Vary.