In a baby, what you might see with strawberry problems is a diaper rash. I'm not sure if that would be an allergy to strawberries or just a sensitivity, though.
It was very dramatic for my nephew. One day they fed him some strawberries for the first time. The very next day, he had a red, irritated ring on his bottom. It cleared up pretty quickly because of course they didn't give him any more strawberries after that.
People don't always think of watching the diaper area to see if their babies have trouble with certain foods, but it's a good idea!