A friend asked about lanolin in my soaps in sweaters, and I thought of my past issues with allergies. At one point, I was allergic to everything, mostly to animals but also to pollen and some food. Then I learned about permaculture and tried to get rid of all the strong chemicals for house cleaning, but my first spring in a house with a garden was still difficult; I thought that I will have to move out to a more urban area, with less plants and their pollens.
Now my allergies are almost gone, I only take calcium once in a while and I'm extra careful during early spring. I also don't eat much of the food I was allergic to, but it's not a big deal if I do (and if it's organic, I'll probably not react to it anyway).
So, while it's not any kind of professional advice, I'll tell you what I do to be able to expose myself to the rich biodiversity of allergens ;) while being allergic to everything:
I try to keep my "zone 0" (where I sleep) super clean, especially of dust, fungus and mold. But I use only gentle cleaners on a daily basis, and if they're not enough, I use the stronger stuff with extra care, and ventilate the place after using it. I have mosquito nets in windows and I clean them regularly too. I let my dog sleep in this room, and it would be better if he wasn't, but he's allowed so I keep him clean too ;)
I don't plant grasses in the garden (they're mostly useless anyway), and I keep plants that produce lots of pollen farther away.
I keep gardening clothes separated from my other clothes, and after working in the garden I change them immediately, and I often take a shower (lots of allergens stick in hair). I think people with allergies should take special care of water resources ;)
During spring, or in stressful sitiuations (which can weaken the immune system), I take calcium with quercetin after changing clothes and showering. That's the only medicine I take now. Remember that there are plants which naturally produce quercetin; I try to have them in my garden.
In general, I aim for as much biodiversity as possible, of animals and plants.
As for the animals, I feel like I can "desensitize" myself to my own; like when I had a horse, I was more allergic to other horses than to mine. With this kind of animals it's easier when they're not stabled, but in pastures with sheds - so the dust, fungus and mold from stables will not stick to their coats. It's healthier for them too.
I don't avoid natural fibers like wool, but I use them as "outside layers" if they're potentially irritating.
In general, I try not to completely avoid anything, even cats; I think it's good to have some contact with the allergens if you can clean them quickly (like when I pet a cat, I wash my hands soon after).
I wanted to share something that really helped with my allergy. I never had any until we moved to the country. I would wake up in the middle of the night sneezing. Then I notice when I drove back into town I would have an attack. I also notice a specific plant that grew that time of year. I don't know if I was allergic to it or it just happened to grow that time of year.
I read a wonderful book about Vermont folk medicine and it recommended using apple cider vinegar and localhoney. The reason for the local honey is it contain the pollen of the plants that you are allergic to or might happen to be allergic to. Also the reason for the apple cider vinegar is for its health benefits. I mix it 50/50 and always have it sitting on the counter.
Interesting! I now have a bottle of organic apple cider vinegar which I used for another recipe (for gargling, to cleanse bacteria) so I can make this mix too. The other recipe was with sage infusion, and propolis tincture.