Your dogs scratchy skin condition can be due to numerous reasons, including food sensitivities. Food sensitivities & intolerance are potentially serious problem that can result in irritated skin, coat & ear, & GIT upset. Dogs that have that have Food sensitivities is known as adverse reaction to food. this is maily due to abnormal response to the protien in the food. The good news is, that of your dog is suffering from adverse effect of the food , these conditions can benefit simply by feeding the right food.