Every couple of months I will get the itchiest, nastiest dry skin on my back. My lower back...on my kidney area...Some of it creates a circle which turns into a sore..and the rest just itches and burns like crazy when I put lotion on it. I also get this on the back of my thighs sometimes but not as often. What could this be? Just regular dry skin or something else? It hurts and it's driving me crazy!