See the question above about celiac vs. allergies. Celiac is a disease whereby the body cannot digest foods containing wheat, but allergies are different in that the food can digest, but those foods cause an autoimmune response. Symptoms can be similar. The same confusion happens sometimes with dairy issues. My husband cannot digest dairy products... he does not produce the enzyme needed to digest them. But this is not an allergy. No autoimmune response happens when he eats a piece of pizza. Similar symptoms, but different causes. Hope that helps clarify. I agree that a visit to an allergist would be smart.
An endoscopy is a good idea, because she could also have an autoimmune disease such as Crohn's, which can have symptoms similar to those of celiac disease.