Has she seen a holistic/integrative doctor? Just wondering if it could be some sort of food intolerance (different from an allergy) or something like that. They can be harder to detect because the reaction could take place hours or days later. I ask because I'm in the process of getting evaluated for some physical and mental health issues by an integrative doctor, and the questions and tests are so much more thorough than at a typical physical. They can check for things like yeast overgrowth, chronic Lyme, and other conditions that a typical medical doctor wouldn't bother to assess.