thinning hair

Question
Kim
I recently acquired my moms poodle, I believe him to be about 10 years old, over the past several months he started to have thinning and straight hair over the top half, (Midway of his back. The rest of his body hair is normal.He is a stocky built toy poodle weighing 14 lbs. I had my vet do a thyroid test this week and the levels are normal. He doesn't scratch this area to cause it, I take him to a groomer and their shampoo has not changed. The vet said to watch him for further signs. He mentioned Cushing disease, just to let me know that might be the reason. However his skin does not look irritated. His level of energy is still good and he has not started drinking more water or urinating more. I am just wondering if there are other reasons why this could happen. Thanks

Answer
Hello Pam,
Stress can cause your dog to lose hair like your dog is doing, though since you have had him for several months now, this may not be the case.  Have you switched food or introduced anything new into his enviroment that he could be allergic to?  
Other than that, I can't think of anything that you haven't mentioned that could be causing this.  

I hope this helped you some and if you have other questions or concerns, please feel free to ask.

Thanks for using AllExperts.com,
Kim