My wife had an allergic reaction to some kind of meds. We are not certain of what it is, but she broke out in hives and now has slight bruising on her legs. She is taking Prednisone, Singular, and Pepsid. The Allergist saiys it might be a mixture of an allergic reaction and vasculitis. If you could possibly give me a better understanding of what is causing this to happen, can you please tell me what it is and why it is occuring.