There is a fascinating article on SciAm about how Allergy Recapitulates Phylogeny. What that means is, that the proteins that our immune system overreacts to, when they are presented to certain cells in our blood and some tissues, are related through the genetic history of the plants that carry them.
The author, Christina Agapakis, points out that this for her is a way to predict whether she will have an allergic reaction to a certain plant or food, and how bad it’s going to be, just by looking at the evolutionary relationship of the plant in question to others that she has reacted to in the past. Quite fascinating !
One notable finding from this mapping exercise is that the strength of my allergic reaction seems to correlate with the plant’s position on the phylogenetic tree. From throat-closing peaches and cherries down to mildly irritating (yet delicious) cilantro my allergic reactions do a pretty good job of aligning to phylogenetic relationships. More evolutionary distant versions of Bet v 1 share less and less similarity with the original allergen, so my antibodies bind less well, causing a weaker allergic reaction.
So as long as you know what you are allergic to (and by “what” I mean the exact protein or substance), you might be able to stay away from similar allergens just by studying the evolutionary tree of whatever it is that you react to. I’m not so sure if that would work with animal allergens, but it’s worth looking into. There sure are people who are allergic to cat and dog and rabbit hairs.