Splits in the epidermis around the heel are frequent, are uncomfortable, and never look very good. They happen when the fat pad beneath the heel expands out sideways beneath the foot and the dry skin cracks or splits to develop a heel fissure. A great 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 of the tomato splits as the insides forces outwards. So it is with the heel. As bodyweight squashes the fat beneath the heel it stretches out sideways from under the heel, it tries to split the skin around the perimeter of the heel. If it is successful or not will probably depend on how supple and resilient that the epidermis is. If the skin is dry, thicker or callused, it is going to tear very easily. If the skin is thicker with a layer of callus, that skin will crack easily and place a strain on the good skin below that can become somewhat painful, perhaps bleeding. Every step which is taken with further more open the split which will help prevent it from getting better. Cracked heels are more prevalent in those that use open heel type footwear, as a closed in shoe will help keep the fat pad beneath the heel in position and help stop or lessen the effects of this.
The most efficient short term relief of cracked heels is to have the callused skin cut back by a podiatrist and then use tape to hold the edges of the split together so that it can mend. The long term protection against cracked skin around the heel should be apparent from the process that was described above. To begin with, weight reduction will help reduce the problem, but this is a long term concern. To help prevent the fat pad under the heel from broadening out sideways and trying to crack the skin, a closed in shoe needs to be used and frequently the use of deep heel cup inserts can help. A podiatric doctor should be consulted on a regular basis to cut back any thick callused skin. Creams should be applied regularly to keep the skin resilient so that it does not fissure. The use of filing tools to keep the thick skin under control may also be used.