Over the last few years, I have noticed that I get migraine headaches and nausea quite often. This seems to happen when I regularly eat dairy products made from cow's milk. My doctor has not found any instance of tumors, so I am pretty sure that's not the problem. I have started eating more soy-based products, and it seems to help. I have not been diagnosed with any particular allergy just yet. Is it possible Is it possible to develop an adult onset allergy to cow's milk?