J.H.
My son didn't have food allergies but had food intolerance.
No all over rash, but very gassy, hurting tummy and the typical "bulls eye" red rash around his anus (see Dr Sears books for more detailed info) this mark was my biggest clue. He had intolerances to wheat and dairy. I exclusivly breastfed and pumped (oh the joy!!) I had to cut out wheat and dairy too aaahhh!!! I am a bread and cheese freak!
It was tough but oh so worth it. He is now 6 and can eat anything. I am sure that by giving his body a rest and a chance to mature (he was also 3 months preemie) was the best thing.
Good luck
J