Peer pressure may also be a large factor, since socially, girls are now 'supposed' to be thin, mainly driven by falsely produced media standards and expectations. The result: young women who feel they must 'be like the norm' to just fit in.
These are two issues that can be overcome with intervention and the help of a doctor/psychiatrist that specialized in anorexia cases. My advice to you would be to have your daughter take a semester off from school and get the help she needs. Afterward, when she is on the road to recovery, a school closer to home may be best.
My best wishes to you and your daughter.
Thanks. Kind words, good thoughts.