My Chihuahua has a red rash-like area on her belly. It has been there for a little while and has not seemed to improve much. However, it doesn't appear to bother her at all. She doesn't scratch the area or seem irritated by the rash. I was wondering if perhaps the cause could have something to do with the type of shampoo we use to wash her or if it could be a condition that the vet should address. We bought some new shampoo for her, but we haven't used it yet. What is everyone's take on this? Thanks for any advice or ideas.