Dwarf hamster with raw spots/missing fur

Hi. I've had my winter white dwarf hamster for about a month. She's probably around 3 or 4 months old, although I rescued her, so I'm not sure.
Just today when she was climbing up the side of her cage (something she does very often) I noticed one spot under her head and the entire underside of her left front leg are rubbed raw, red and missing fur. They don't appear to be bleeding. She does itch herself and clean herself, but I'm not sure if it's really excessive or not.
The photo is very blurry, but that's the underside of her leg as she climbs up the cage.
She is still active and eating and drinking.
Help?

[ireneo]

She could have some kind of skin mite that causes itching, hair loss and skin irritation. It would be best to have her checked by a vet who can do a little skin scraping and check it under the microscope. Once they know what they're dealing with, they can give you the proper medication to treat her. You will definitely have to clean her cage completely. If she does have skin parasites, they will just get worse. I don't have a lot of confidence in the meds you buy in the pet store. You have to know what's going on first.