What can cause liver enzymes to elevate?

I am 22 years old, in decent shape, and I don't drink alcohol. For the past 3 weeks I have been itching like crazy day and night. I have no rashes or raised bumps but its getting to the point where I am scratching so hard that I am breaking the skin. I went to the doctors and she prescribed me a bunch of allergy medicine and lotions to try and see if thats what it was, as well as having blood work taken. She called me and told me that everything was normal except for my liver and that it was reading very high. All she told me was that she was concerned and to come back in a month to have blood work taken again to see if the results changed. So now I am freaking out as to why I'm itching and why my results are what they are. None of the allergy medicines are working so I know its not that.My doctor sounded worried but didn't tell me too much. I have been tested for Hepititus and that was negative, so what else could it be? What would elevate the liver enzymes? Should I be worried?