Breaking out in hives... allergic "sometimes?"

My daughter breaks out in hives about once every other week for the past 4 months. When it happens, it's always just on her face, and it's bad around her eyes especially. Her pediatrician made light of it and said it's no big deal, just do Benadryl, kids get hives, whatever.

But I'm not willing to take that explanation anymore because it happens too much. I haven't been able to pin it to anything until now because it's inconsistent, but I think it's dogs and cats-- but only sometimes! Does that make sense? We have a cat and my daughter has no problem playing with her, burying her face in her fur, etc., at least most of the time. It's never been obvious that she broke out after playing with the cat, but there's also no other obvious trigger. It mostly has happened in my living room randomly when we're watching TV or doing a craft or something.

But now she's broken out twice after playing with a dog outdoors, so I'm pretty sure she is allergic to dogs... but again, just "sometimes." She pets lots of dogs and doesn't have that reaction.

Is that normal? Can kids be allergic to the same animal sometimes and not other times?

Re: Breaking out in hives... allergic "sometimes?"

Why not make an appt for allergy testing? I had DS tested at 18 months for random things and found my fears were valid.