Cracks in the skin around the heel is usually both unpleasant and painful. This issue is because of the thick or dry skin, on and around the periphery of the heels. The skin on your feet is generally more dry and dehydrated than the skin in other places on the rest of the body probably as there are no sebaceous glands within the thicker skin on the soles of the feet. Due to this, the skin around the heels might lose suppleness and elasticity due to that deficit of moisture. Because of the pressures of weightbearing, that dry skin can start to split and it can cause ugly, painful cracked heels that could sometimes bleed. There are a number of factors which raise the risk for the cracked heels such as higher loads, greater weight, poor fitting footwear (especially shoes which are open at the back), genetics, unhygienic conditions and poor self-care, as well as dietary inadequacies.
To avoid cracked heels, always try to wear well fitted enclosed footwear that allow the feet to breathe and steer clear of footwear that are open at the back. It is very important to stay well hydrated by drinking at least two litres of water per day as that can help. Exfoliate your skin frequently and moisturise daily with a decent ointment. If it is more severe, this should probably be done twice a day to begin with. There are many recommendations that omega 3 and zinc nutritional supplements may also help (however they really do need to be used with all the other solutions and not on there own). It will also help to avoid excessive exposure of the foot to water or moist conditions. It is important that you clean your feet with warm water as opposed to very hot water. If these types of strategies tend not to help, then see a skilled podiatrist. They can take away the thicker callused skin and give additional suggestions about how you can self treat.