A few days ago I developed a quick spreading and burning rash on my torso, neck and arms. I went to the hospital where I was given prednisone and benadryl.They thought it was something I ate but I had nothing that I hadn't had before. I was told to take benadryl for 48 hrs. I was feeling better the next day and afraid to eat anything weird,I had a banana smoothie. Within minutes I started getting a rash shortly after. Didn't think it was the smoothie. Today is the fourth day after the first rash. I just had a banana and almost immediately felt a burning in my chest and rash on my arms. thinking back, the morning of the first rash I had a banana. Took a benadryl immediately. Can this be an onset allergy? I never had this before