Yes, it is common indeed!

Interestingly, it follows with what my allergist predicted to me about my cat allergy years ago. Sadly, it was so severe I had to find a new home for my cat (many, many years ago now).

Anyway, he told me that initially I may find I react even worse to any exposure to cat, but after a year or so... my immune system would no longer be on heightened alert for it...back to rest mode... and I would not react as severely. And it followed that course... initially I was extremely reactive after even setting foot in the house of someone with a cat, to now, years later, I can be in the house for hours and even pet a cat without reaction. I would never own one again, because I'm sure it would start all over again.

The fact that your body is responding so negatively to exposure to gluten tells you that you are indeed gluten sensitive. Removing a food and then reintroducing it gives you the best idea of whether it is a problem food for you. Sounds like gluten is a problem for you. Dairy is a big problem for many people, too.

You should strive to be 100% gluten free. It really is an all the way sort of thing if you want your immune system to stop reacting. Having it once in a while just continually reactivates the immune system, keeping it in ready mode. After a year or so of really strict compliance, you may not react as severely to an occasional exposure. Still, you should strive to be 100% strict, although accidental exposures do happen occasionally... and you may not react as severely to occasional exposures down the road (unless they are repeated).