dry skin

My skin gets so dry especially around my hands. I put lotion and mosturizer, it works for a while and then I end up washing my hands, then my hand looks so cracked and dry. Sometimes at night, I scratch my fingers then it starts to bleed. I am thinking that it has to do something with what I eat. I notice if I eat sweet foods, my fingers itch, or maybe it is just psychological. The only thing that heals my fingers from dry skin is cortizone which was prescribed from the doctor. I could not find that specific cortizone in the drug store.