I read recently that flushed face and itchy skin is a sign of allergy to tannins or something else in beer and red wine...something on grape skins and malt maybe?
I get headaches with certain beers and breweries as well, but I have more problems when I drink later in day or evening in quantities of 3-4 pints....the headache comes on fairly quickly and intensifies with sleep. When I drink in mid day to mid afternoon, my body processes it better, and if any it is milder pain and subsides usually before bed.
I am thinking that as I age I am transitioning to being a "beer for breakfast only" kind of guy....and then dinner at 3:30p (and I am not that old).