My son has a peanut allergy which manifested in the same way. We were then told to have a component test done on his blood to determine which proteins he was actually allergic. It was explained that some are more commonly related to anaphylaxis while others tend to just cause rashes, etc. He ended up testing positive to one that is considered "bad", and he has been in OIT for awhile. So far so good - but I recently heard of a child doing the same with milk OIT and the child passed away. Very scary stuff.