Allergies are weird! I lived most of my life afraid of eating raw egg, even though I am sure i haven't been allergic for years it's only recently I've been eating things I *know* have egg in them.

I wish I could have outgrown my dog and cat allergies, but they are waaaay less bad than they used to be.

I hope your niece grows out of it - seriously, I am pretty sure I was still reacting, but not badly, when in my late teen, early 20's.