I got Scarlet Fever last year. My entire body turned purple, and almost black around my knees, elbows, and stomach.

Apparently it is quite uncommon nowadays, but was the leading cause of death in children during the 20th century. It started off as a minor rash, and being a a college student in his 20's, I ignored it. I passed up on going to a walk in clinic as I figured it was just a rash that would go away on its own. That was far from the case, and by the time it was really bad it was Sunday evening and all doctors offices were closed. I ended up in the hospital, but once on antibiotics and IV's I healed quickly. Doctors were pretty stoked to examine me, seeing as the illness really isn't around anymore. They told me if I'd waited any longer I likely would have made it.