Why is my dog itchy? And should I take her to a different vet?

She’s been scratching and biting herself almost constantly for about a month now, and she has begun developing patches of small, irregularly-shaped red irritated spots. The worst ones are a little bloody, and the fur is thinning and falling out at the spots. I just moved last week and took her to a new vet in my new neighborhood on Tuesday, and he said that it wasn’t ringworm (he looked at her skin with a UV light to confirm this). She doesn’t smell bad, so I’m thinking it’s not a staph or bactierial infection (from syz’s description of these from a different thread on this topic). She has seasonal allergies that manifest in the form of very mild eye irritation in the late fall in Colorado. She had no symptoms here in NYC last fall, though. And I doubt that it’s fleas because no one else in the house has been suffering at all, and I don’t see flea dirt in her fur.

The vet said it was probably just dry skin and sent me home with this spray that seems to give her temporary relief and make the spots a little better – but she’s developing more, and much worse ones all the time. I think it must be more than dry skin. The vet wants me to bring her back in, which I will do today – but I’m a bit upset that he loked at her fur falling out and these spots and called it normal shedding and dry skin, and that I seem to be taking her in for an office visit an extra time, when it seems to me that they ought to have been taking things a bit more in-depth in the first place. Since they charge $50 just to come in, I’m somewhat miffed. After this problem is resolved, I’m thinking I’ll try another vet – or do you think that they are not being lax, and are doing what this situation calls for?

More importantly, what the heck is bothering my poor pooch?