This is a guess or suggestion.
I found out many years ago that you can be allergic to x, y or z and not have any response large enough to really know until for what ever reason you subject yourself to multiple allergy items all at once and then misery starts.
I found out that being allergic to sweet clover, shell fish and chocolate in a combined dose, even a small amount of some, big of others, is not a good idea.
It happened to me so it is just a thought.
