Maria Holic Vol 4

Maria Holic by Minari Endou. A Romance manga rated Older Teen, published in English by Tokyopop.

Kanako Miyamae breaks out in hives whenever a man touches her, so she transfers to an all-girls Catholic school hoping to find true love. Instead she discovers that the angelic, beautiful Mariya is actually a sadistic boy in disguise, and he's not about to let her reveal his secret.