Right now, watch him carefully and determine the level of reaction. Mild, rash and vomiting is okay, but anything more you should get him seen by a doctor. I'd call the nurse help line or after hours service, so that they have a record if you need to go in.
I have severe food and plant allergies. Although my oldest has tested only for soy and plant allergies, we opted for in home care. No nurseries or daycare. With #2, allergies are also present.
We encountered some allergy unfriendly DCPs and see peanut butter and soy all too often. Even providing snacks, they would touch other foods, THEN the food for the kids with allergies... Um, HELLO!!! The safest thing is to NOT have them around people and places that there is a high exposure risk. Poor food hygiene and contamination practices are not to be taken lightly. Many schools here don't allow peanut butter or PB&J sandwiches. So, I don't get why daycares or church nurseries should be any different. If they won't accommodate, then the best thing is to remove your children from the risk.