Egads, that is a tough one! I'm 100% sure we are so attached to Yoda that the skin kid would have to adjust, unless it was life threatening for the kid. But on the other hand, it really wouldn't be fair to the kid though, to always have a rash because of Yoda. If it was fixable by drugs or medication, well, then yes, that'd be fine and we'd do whatever it took so the child could co-exist with Yoda. I have heard of people giving up Yorkies due to problems with kids, and that's just very sad when I hear it.
Luckily, we know of at least two families (both close family members) that would spoil Yoda rotten (probably more than us even!) and could take him in as a last resort. One of the families is Yoda's godparents, in case something ever happened to us, they would take care of Yoda for the rest of Yoda's life, and we have financially arranged for them to do so as well. And they love him just as much as we do and he gets treated like royalty when he "vacations" there.
Giving Yoda to someone else would be the absolute last resort, though. We made a commitment to him when we adopted him that we would take care of him for all of his life as best we could and we think it's very important to stick to that commitment to him as he has given us so much love, happiness, joy, companionship, friendship, and good luck.
Do you think the situation would be changed if the KID came first? And say, the kid was 2 or 3 years old, then the family got the Yorkie? Then later, the kid gets an allergy a year later?