Dehydration will cause your skin to be dry and flaky and itches , just like what we call winter skin, and can also cause your sips to be very dry, chapped and red from the dryness, but the way you describe your symptoms, you have something systemic going on,, like an allergy.
Operating Standards are a set of guidelines or regulations that people have to meet or exceed while in operation. It makes sure that the product that they produce is of acceptable quality for consumption by the public.
The operational definition of an empirical term (i.e., a descriptor of some element of physical experience) is the description of a specific process, or set of validation tests, accessible to more persons than the definer (i.e., said to be publicly accessible), whereby it is (or can be) repeatedly measured or tested.