Splits in the epidermis around the heel are common, are painful, and do not look very good. This occurs if the fat pad beneath the heel stretches out side to side beneath the heel and the dry skin cracks or splits to produce a heel fissure. A good way to understand these is to use the example of a tomato being compressed. As you apply pressure to the tomato to squash it, the skin around the tomato cracks as the insides forces outwards. So it is with the heel. As bodyweight squashes the fat underneath the heel it stretches out laterally from beneath the heel, it tries to tear the skin around the perimeter of the heel. If this succeeds or not will probably depend on how elastic and strong that the epidermis is. If the skin is dry, thicker or callused, it is going to crack without difficulty. If the skin is thicker with a layer of callus, that skin will split easily and put stress on the healthy skin below that will become rather painful, sometimes bleeding. Each step that is taken with further more open the fissure which will help prevent it from healing. This is more prevalent in those that wear open heel type footwear, as a closed in shoe can help keep the fat pad under the heel in position and help avoid or decrease the effects of the split.
The most effective short term relief of Cracked heels is to have the callused skin removed by a podiatrist and then use strapping to hold the edges of the crack together so that it can mend. The long term protection against cracked skin around the heel should be apparent from the process that was explained above. To start with, weight reduction will help lessen the problem, but this is a long term issue. To help stop the fat pad under the heel from broadening out laterally and trying to split the skin, a closed in shoe needs to be worn and frequently the use of deep heel cup insoles can help. A foot doctor should really be consulted on a regular basis to debride any thick callused skin. Emollients really should be applied regularly to keep the skin supple so that it does not crack. The use of pedicure files to help keep the callus under control can also be used.