Personally, because he has such bad skin, I wouldn't bathe him that often. It can cause skin irritations. But, if you HAVE to bathe him, I'd recommend getting a presrciption shampoo from your vet for skin problems. If you can't get a prescription shampoo, go with the mildest oatmeal shampoo you can find. Don't use anything with colours or fragrances and don't use cologne or anything like that. If you can, try not to bathe him more than twice a month. You don't want to take a chance of irritating his skin more. I was a groomer for several years, and have seen more dogs with bad skin because people were bathing too much and using harsh shampoos n stuff...