I found this site when looking up dog rashes and allergies, actually.  Sam has this 'spot' on his side were he's loosing all his hair. It looks like some sort of rash, or maybe mange? He's had bald spots before...one was when a tick bite got infected, and another time the same sort of rash came up. The last time, though, it went away, so we've been hoping this one would do the same. Unfountunately, it seems like it's been getting worse. We put some vasaline on it, but it didn't seem to do anything. It first appeared when I was petting him and I found this 'lump' on his shoulder. The skin is very dry and flakey, like a big calouse.

He's also been very itchy lately...the skin under his arm is starting to turn red and is getting iritated from him scraching the same place so much. He's had a rash before under his back legs that seems to appear every winter; took him to the vet for it, and they gave him some kind of cream that worked really well. He also licks his feet and under his legs a lot.

Going to take a trip to the vet, and I'm hoping it's something easy to take care. Does anyone here know what it might be? Maybe an allergy?

Tried to get a good shot of the dreaded spot, but Sam kept squirming and wouldn't stay still.

It could be an allergic reaction to the grain fillers in the dog food.  I would switch to a grain free and by-product free food.  Also, some powder laundry detergents use corn as a filler  .  (I was told this by the wife of a doctor.)  Contact with an item washed in a detergent that has corn filler could cause a reaction. 

We went to the pet store and got some samples of "Natural Balance" at a table they had . Added a little of the "Potato and Venison" to his food and he picked it out of his bowl and left the Pedigree. We got a few different types and are going to try and add a little to his food and see if it helps at all -Although we'll skip on the "vegetarian formula"- We're also going to start adding a little olive oil to his diet and see if that helps .