I once had a serious allergic reaction to an anti-biotic. However, it wasn't your average itchy rash, swelling kind of reaction. First I turned bright red all over, then I began to itch all over (wanted serious meds at this point), then I got this crazy vivid rash all over (it didn't hurt or anything), the next day my joints swelled up: knees, ankles, wrists. Soon after that I was unable to get up as my spine was affected. My limbs just wouldn't operate properly. I started to think I was either going crazy or I was gonna die at this point. I saw all kinds of specialists who thought everything from Lyme disease to Leukemia. They did NOT think it was all from an allergy reaction. It took a month to get over this deal and I was pretty weak for a good while. It was so weird. I never do anything in an average way! It started to happen a second time to a different anti-biotic. This time I went straight to my Dr. and demanded epinephrine and steroids and it stopped the reaction before all the other steps happened.