Okay, Please look into symptoms of salicylate intolerance. Many people with MCAS are allergic to asprin which contains salicylates. Salicylates are in many fruits and vegetables. Nearly all herbs and spices are high. I had to go on low salicylate low amine diet and I would be dying right now if I had only reduced histamines. I had all of these symptoms like your daughter and got way, way better after lowering my salicylates. I will list some of the things I eat that keep me from having hardly any symptoms. First meal is usually hamburger patty with salt and garlic powder only and no other spices, and green beans. Second meal would be sirloin steak or chicken with either small amount of sweet potato or green beans or broccoli. There are other low salicylate vegetables she could eat but until you learn everything yourself which is confusing at first this should help her symptoms pretty quickly if this is all she eats for about a week. I also eat clarified butter with meals which is adds flavor and is satisfying. I don't know if you'll see this since your post was so long ago but maybe it will help someone else.