Just out of interest, at times when I have taken prednisone for my asthma it has worsened my UTI situation.  So it isn’t just over exercise and stress raising my cortisol levels but also when I actually take it in extremely high doses to combat chest problems that it irritates my bladder and makes me more susceptible to flare ups.  I now believe that I have some kind of interstitial cystitis thing going on and that asthma medications and exercise and stress worsen the episodes.  So if your child has any allergy like a food type allergy I’d assume it is because they are slightly over treated.  Since they can never get the levels correct exactly and its AS possible to under treat and cause allergies as what it is to over treat and cause allergies in such individuals you are better off avoiding the triggers AT ALL TIMES.   Prevention is better than the cure anyway often, which more often than not is usually anti biotics in my case, which in themselves wreck the immune system.  Anti histamines also have their side-effects too.  There are some occasions where you simply cannot avoid some allergens, but you can work at reducing them.