Poor baby. He probably has never been socialized properly. Our poor buddy was like that when we got him from the sorry excuse of a breeder. After we bought him (fell in love with his face). He was extremely shy and would cower if we tried to pet him. Come to find out, he had lived his entire life outdoors in a kennel with little to no human contact. Today he is a sweet loving dog. For the skin condition try using Missing Link. It is sold at Petsmart and other stores. It is a powder that you add to their food. We put Ruby (terrier) on it and her skin condition has improved dramatically. It will just take time and patience with him. And you may end up getting nipped a couple of times. Ruby was found wonder the streets and we have had to work through some jealousy issues with her. But we have had her for two years and she is progressing nicely.