C.S.
Hi M.! It's so hard when they are small and can't let us know about other symptoms, isn't it??
My niece was visiting us over Christmas and is confirmed allergic to peanuts and other legumes. We were scooping out ice cream, and were sure to give her the chocolate first and not the peanut butter twirl. When we went to give seconds, I completely forgot and scooped her chocolate with the scooper without rinsing the scoop. She finished her bowl, and then as she put her spoon down, exactly what you explained happened.
They gave her an antihistamine right away, in case she would start having a serious reaction. I felt so bad!
C.