Hi Nanny,   There are tests that can determine what you are most likely allergic to. They are reliable, though not guaranteed to be absolutely 100% accurate, especially in kids. But many people have what is known as a food intolerance, rather than a food allergy, to dairy products. You may have heard this called lactose intolerance, and it can be discriminating to a particular type of dairy product. For example, my daughter is intolerant only to parmesan cheese, but has no real problem with anything else.   As far as the Allegra, it's not likely that's having any effect at all. Antihistamines are not known to be effective in treating food allergies. The only treatment for food allergies is to avoid what you are allergic to.   If you want to explore the possibility of a dairy allergy, I'd suggest you consult with an allergist, a doctor who specializes in allergies.   To your health, Kathi