bacterial infection
"Pain and swelling in the vicinity of my tailbone led to an emergency room visit where I had a pilonidal cyst drained. After the doctor incised and drained my cyst, he prescribed me Bactrim and Keflex. He explained that the Keflex was intended to treat the infection if it was MRSA while Bactrim would cover all other bases.

A week into my 10 day course of antibiotics, I went to bed with a developing fever. In the morning, I awoke to discover that my entire body was covered in a red, splotchy rash. I immediately went to a medical professional who informed me that I was likely having a severe allergic reaction to Bactrim. I was informed that my fever and rash would persist for days to weeks and may progress to anaphylaxis."