Yeah-- wow-- this sounds like a massive dose for a challenge, in light of the fact that this is a kid with reaction history.
DD's reaction history with egg has been very severe, and very low-amounts.
She would NEVER have tolerated that kind of dose. We challenged her with 1/40th of an egg, well-baked, over five hours. It wasn't to establish where a FAIL would happen... but to establish whether it would be possible to dose her at home well within a window of safety.
KWIM?
Different approaches, and maybe-- different goals?
I don't know. I think that our allergist could have gone either way on it, but this was our call, and we wouldn't have done the challenge that you describe. Not then. Maybe now, after several years of dosing. Our allergist is a Sinai-trained guy; he tends to view it as a matter of seeing what is SAFE, not pushing to see what isn't. Not in someone with known anaphylaxis history, anyway.
I think that there's still anaphylaxis potential, but I also think that we've pushed the threshold high enough that environmental exposure is less likely to be a severe risk. It's opened up some quality of life, for sure.