Food allergies will affect each person differently. If you are allergic to raisins, you are also allergic to grapes. Grape allergies usually stem from the yeast that grows on their skin, and will go along with anyone that has a yeast allergy. There are also sulfites in grapes, the sulfites can also cause an allergic reaction. The best way is to have an allergy test run by a doctor. This will give you a list of everything that you are allergic to.