Allergist

Has anyone had to take their lo to see an allergist ? My daughter has been referred to one after getting hives from eating eggs and puking after eating bananas (both of their own so thankfully it was easy to nail it down to what caused the reactions) It was a pretty rushed over the phone well-ness check so I completely missed asking her ped what to expect in terms of what exactly do they do when she goes to see one?

TIA 🙂