This video points out the top ten warnings signs to a gluten intolerance/allergy.
Although I personally think the first two minutes of the video are incorrect as they do not mention that oats are gluten, describe Coeliac Disease as an intolerance and states that a blood test is the only way to be diagnosed for Coeliac Disease. This is wrong as (in the UK at least) you have to have an endoscopy and biopsy as well.
Nevertheless, the rest appears relevant.