What Causes Dry And Hard Skin On Palm And Fingers?

my palm & fingers skin gets hard and dry, even cracks comes, using DipSalic F Ointment softens the skin & helps in healing of the crack, kindly help me with the permanent cure for this, is this is due to some deficiency in the body & can this be cured permanently, or I need to have the dependency on this cream for my entire life time.