Hi Rachel, For me the flare up is any symptom at all, not just gut, but itching/thrush, feeling worse all over. This can happen when candida is dying off as well, so sometimes the symptoms are healing symptoms.

But things that can cause flare ups, are not always sugar, but things that tend to aggravate the condition like eating yeast/cheese and drinking coffee, having vinegar or something like that.

I know that yeast can cause allergies, as can mercury and I find for me at least it's not so much allergy foods, but foods that feed candida that are the problem.

Also, there are healing symptoms that mimic allergic reactions! So sometimes eating healthy foods can cause so-called allergic reactions, when they might be part of healing and die off. Itching can be part of that as well.

I am careful with getting into the allergy thing too much, I just avoid stuff that messes up my gut and feeds yeast, if I thought further about each food, I'd go nuts because I already have a limited diet. I'm pretty sure the foods I have are "ok" (cross fingers).