Painful fissures can form around the edges of the skin on the heels. The edges of the heel are subjected to a lot of shear stress, working with the plantar fat pad under the heel. If the skin becomes drier and/or the fat pad beneath the skin starts to break down, the skin on the heels can start to become callused and cracked. The skin on the feet can dry to circulatory and/or hormonal changes which together often associate with ageing. However, sling-back sandals can provoke cracking of the heels too.