Could be any number of things, actually. But since the pattern is broad, it's most likely an allergic reaction to something. She should eat a very simple, bland diet of nothing but whole foods for awhile and do some probiotic supplementation (kefir, yogurt, Primal Defense). If you can help her with kinesiology you can test the things she's been eating prior to this to see whcih ones should be out of her diet permanently.