Cracked heels are known medically as heel fissures and are most often the result of extremely dry skin, or xerosis. In fact, deep cracks can form along the back edges of the heel that are painful and sometimes deep enough to bleed. The first sign of getting cracked heels is the development of dry, hard, thickened skin around the rim of the heel. This is called a callus and may be yellow or dark brown discoloured area of skin. Initially small cracks over the callus are visible. If left untreated and as more pressure is placed on the heel, these cracks become deeper and eventually walking and standing will be painful. The cracks may be so deep that they begin to bleed.