Daughter is obsessed with herself: Tough Call

My daughter is obsessed with herself and with having other people think she is pretty and popular. I realize that this sounds like normal teenage behavior but I think she is on the extreme end and I am worried she may be a narcissist. She gets very angry whenever anyone questions her beauty or her ‘status’ and she seems to consider it her God given right to use other people as she sees fit for her own ends. We have had a strained relationship for a few years now. I love her dearly but I have very little influence over her so my words don’t really change much for her. She is a popular person and she always has a group that follow her but she has trouble holding onto the same friends for long – and close friends always leave her. I am worried that unless she changes she is going to end up alone in life. How can I know if she really does have narcissism and if she does is there any effective treatment for this condition?