We suspect blueberries were to blame for the first attack, so we've been keeping here away from them. But tonight I made mixed berry Kool-aid, which apparently has blueberries in it according to the picture on the packet (although the ingredients only state "natural ingredients" and not specifically blueberries) .
I didn't notice the picture of the blueberries when I made it and served it to my kids. We were in the ER about 15 minutes later.