Can you tell me is there a pill/medicine you can take daily to prevent a allergic reaction beforehand?

Depends. if you want to control urticaria for exampl,e then your doctor would prescribe you a medicine to take to control the symptoms, but if you are allergic to a food or a medicine and want to take a medicine to prevent an allergic reaction due to such food or medicine you are allergic to, this is not advisable, see your doctor or your allergist and discuss your allergy problems with, take care.