I have mild eczema and it flares up during spring time with pollen and warmer weather. I can't help but scratch the back of my hands until it bleeds. Why do we scratch when it is itchy? The more I scratch, the more itchy it becomes.

Also why can't I stop scratching even if I know it is a bad habit. It tears the skin and make it bleed, making healing even more difficult. Why is there a "nice" feeling when we scratch?