We Think We Figured It Out

On 02/26, Melanie had an allergic reaction to something at Serafina's Birthday Party. She ate 2 grapes, a cupcake with no frosting and a bite of pizza. Her eyes got red, puffy & watery, her nose was dripping and she was rubbing her face like she was tired. We got her home, gave her a bath and she was much better. Melanie had cupcakes and pizza before but not grapes. So we cut grapes out of her diet, thinking that was the cause.
Fastforward to Melanie's birthday party yesterday (no pics unless Betsy/Jason or Linda share theirs - we didn't take any). Melanie had a smash cake and a few minutes after her experience with it, she started getting red splotchy spots where the frosting was. No terrible reaction, but we did wipe off the frosting pretty quickly.
Today, Melanie had a piece of chocolate/chocolate cake with Gramie, Daddy and me and there wasn't a reaction at all. Well, not a skin reaction, anyway. She LOVES chocolate!
The culprit? We're 99.9% sure she had a reaction, possibly allergic, to food coloring/dye. The cupcake she ate at Dana's was the confetti kind, with food-dye spots throughout the much consumed cake, and the frosting she ate yesterday was yellow, pink and blue dyed. We will, of course, confirm/check with Dr. Hiben when she goes in for her next routine checkup, but that's got to be it! In the meantime, I'm tempted to smear a little red frosting on her arm to see if it gets irritated. I got a lot of frosting I can test her with...