The thing about rashes is that many times doctors do not know what to do about them. They could be viral or an allergic reaction but doctors just by looking at a rash can not always give a correct diagnosis. There are just so many types of rash and so many reasons on why it could have happened. I personally, get very worried when I see a rash that I have no idea got there. Sometimes you know if it is bug bite or something you ate but when it just appears it can be scary. I always have benedryl on hand though.