those bumps in that picture almost look like what my girl gets when she gets fleas, she is very sensitive to them and I have to stay ontop of it. Have you checked for fleas or other bugs? the smell thing sounds like a yeast issue and the flaking. it is most likely an allergy but IMO giving benadryl as a solution isnt gonna fix the problem you may have to change foods I dont know much on the food you are feeding but does it have grains in it? what are the ingredients? and when you say you switched foods before but stools got to soft how long did you give the new food before you decided it wasnt working?
for bathing always use dog shampoo others can dry and finding one without added scents is best i like the oatmeal ones I get for mine. also how often are you bathing? excessive baths can deff dry the skin out so keep that in mind as well. a thing you can try is adding a fish oil capsul to his meal 1x a day or whatever the recommended dose is on the bottle, it can help the skin and coat.
for bathing always use dog shampoo others can dry and finding one without added scents is best i like the oatmeal ones I get for mine. also how often are you bathing? excessive baths can deff dry the skin out so keep that in mind as well. a thing you can try is adding a fish oil capsul to his meal 1x a day or whatever the recommended dose is on the bottle, it can help the skin and coat.