My symptoms are much like others described. I was prescribed Bactrim for a recurring UTI. I have never taken it before and have never been aware of any drug allergy. I took the Bactrim two times a day for five days. On the fifth day I began to develop a fever, with very cold chills, then very hot. The lymph nodes in my neck and the back of my head swelled up that evening and were painful when pressed. The next day I stayed home from work and my temp was up to 100.1. By evening that second day, I had developed rashes on my elbows and feet. They were itchy and raised. The next morning, which is today, the rash has spread to my shoulders, arms and thighs. It is not raised, but is a mass of small red dots. My face is also very red, and I think that my lips feel swollen. It has been good to read here that these are likely the result of the Bactrim. Much better info here than I got by calling the pharmacist! The only reason I looked in to it being a reaction is that my mother in law has had allergies to sulpha drugs, and has mentioned rashes. I agree that it is also interesting to here that it has happened to others either after the prescription had finished, or right around that 5 or 6 day mark.