As an "allergy mom" myself, I am willing to accommodate most allergies. I have a child who is mildly lactose intolerant in care, so Mom brings what she wants him to drink most days. She was supplying lactose free milk, but she thought that might be causing him stomach problems, so now he has juice on occasion but mostly water while here. I also have another child allergic to tree nuts, and parents have provided me with both Benadryl and an EpiPen. My own son is allergic to peanuts and therefore we are a nut-free home anyway!
Bottom line, talk to your potential provider about the entire scenario. Discuss all possible causes and reactions that you have discovered so far. They will then tell you whether it is something that they can deal with.