How can I get rid of flaky skin? What is causing it?

The skin on my arms is really flaky. The skin is soft and feels moisturized, but it's really flaky. If I put lotion on them about 10 minutes later when the lotion has soaked in the flakes start to reappear. I'm so confused!!!! I've been drinking more water, staying out of hot showers, and tried exfoliating. Someone help me! =[