This is my first time on the forum. my sheltie is almost 6 years old and the past year she has developed a reddish rash on her underside, and to a limited degree on her back. The vet pointed it out to me and she was put on simplicef. The explanation was allergies.It cleared up.: I did some research and had read it could be due to low thyroid so I had her tested for this. Her level was 2.2 the first time and I had her tested six months later and it was 2.7. I have been washing her once a week with an anti fungal shampoo, but this time around, it seems to be getting worse.It has crusted over in some places, dried up and then just left a very red underbelly. Still on simplicef and no relief. I am now going to take her to a dog dermatologist and will let all know what I find out It does not seem to be itchy and that is the reason I did not notice it initially If anyone has any advice please let me know.