Our son had some type of food allergy when he was 1. But, at 1, we had tried several things and tried figuring it out on our own. We thought it was milk, but then decided it must be eggs. He had a blood test and it came back positive for both eggs and milk. Now, we were sure that he wasn't allergic to milk becuase of all of the testing we had done on our own with different foods. So, then we had the skin test done and it came back with the same results. He was not allergic to milk though, even though he tested positive.
I guess, if it would help put you in the right direction on what your child is allergic to, then it might be a good idea. I just would worry about the false results that can happen a lot with kids. I don't know why it is that way, but you just have to be prepared for that. Also, the blood test would be a lot easier than the skin test. The skin one, you have to have a scratch mark for every single food you are testing.