What is the definition or description of: novocain allergy?

Natural v. man-made: There is about 1 in 1000 people that are allergic to Novocain. The allergic reaction is the same as any other allergic reaction...swelling, itching and possibly even death. But the industry has, for many years, been using an altered version that has a much lower allergy rate. But just think of the allergy like any other allergy like to peanuts.