The rectus abdominis muscle (which runs vertically down the abdomen) acts as a synergist and supports the oblique muscles in the movement needed for a side crunch. Although side crunches can improve abdominal tone, you can't spot-reduce your midsection.
Maybe test her theory of being allergic to cats or maybe even some of the scents or something from her friends house. She should also consult a doctor to be sure.
