I have noticed numerous postings on skin conditions and lip sores so I wanted to post my experience. My dog had lip sores and was constantly scratching all over as well. Antibiotics didnt help but adding prednisone did. Then the vet switched him to azathioprine. She said it was less harsh on his system. What she didn't tell me is that it causes bone marrow suppression in 10% of dogs. What she also didn't do was blood tests for cell count both before and every two weeks after the course started. One month later he started getting sick and $4k and one week later he was dead at 6 years old. I lost a great dog because of this drug and this vet. I'll never ever not investigate something a vet tells me again. So, if your vet mentions this drug and neglects to tell you the risks or do the blood tests beware!