Over The Past Year I Have Taken Several Different Antibiotics

Over the past year I have taken several different antibiotics for ear infections. I have developed a skin rash with the last 3, doxycycline, amoxicillin, and now azithromycin. They are small itchy bumps, like a pimple, on my entire trunk. Prior to this I have never had a reaction to any medications. What is going on and what should I do for this?