Reaction 24 hours later?

faith194

DS is MSPI.  My grandmother didn't know this.  She snuck a little frosting(more of a glaze, I guess). The moment I saw her say "Oh you want some more?" I stopped her. She said she had no idea. . .He probably had less than a teaspoon. . .Anyway, I noticed a little rash(more of a ring) on his bum and he threw up everywhere 24 hours later. His diapers have also been very runny, too, since then. He is acting fine, an doesn't have a fever. 

Is it possible to have a reaction 24 hours later?  We've been so careful since he was diagnosed at 6 weeks.

magdusia

it's possible to react a week later.  We don't have MSPI but we do have a milk/soy allergy (and a few other).  His soy is the lowest out of all his others and we tried re-introducing it a few months ago and his diaper rash came and left for a week.