Have had a horrible reaction to Bactrim. Started with loss of appetite, body aches and headaches within a week of taking Bactrim. Progressed into fever and the chills by a week and a half but just thought I had the flu. After taking Bactrim for 13 days I started breaking out with hives on my face, neck and chest which later spread to my arms and legs. I was diagnosed with an allergic reaction to Bactrim, pumped full of iv fluids, steroids and anti-histamines once they figured out what was going on. I had a fever of 101-102 for over 4 days. I was dehydrated and had a low white blood cell count. I'll be taking oral steroids and anti-histamines for 5-6 days. Such a horrible experience, I'll be glad when I won't be on any more of these medications!