Are there any equivalent (or nearly so) natural "anti-allergens"?
Nothing readily obtainable works like epi, and for food allergies, nothing other than figuring out what factor in modern society has made peanuts suddenly more dangerous than any bullet ever developed.
For a respiratory allergy, pretty much any other way of getting small amounts into your system works. If I go out early in ragweed season in shorts and let my legs spend a day or two puffy and red, I can usually get through the rest of the season without sneezing. A cat scratch may look like a horrible injury on me with massive swelling and redness for a few hours, but it seems to inoculate me against the eye/nose irritation for months. Local raw honey is a much more pleasant way to accomplish similar results with plant allergens, but it does seem to take a lot.