If you have a severe allergy, you can also ask for a manager to make it for you. They'll make it in a separate area in the back, and tell you which toppings are "safe" (sometimes they only have certain toppings up front, where there's a greater risk of cross contamination).
I love Beaches and Cream. I'm a vegan and my husband is allergic to dairy. We always go there once during our trips and get waaaay too much ice cream.