If I eat gluten the reaction is almost instant. *not INSTANT, but within a couple hours, basically once it gets past my stomach thats it*. I don't buy the it takes weeks for Acne to form thing, its not true in my case. I think once I eat gluten the reaction can CONTINUE for weeks, but it starts up right away within the hour or two.
I eat ice cream often with no effect. Just had a bowl. Yum! =)