Cracked heels are primarily caused by dry skin and a lack of moisture in the heel area. The skin around the heels has fewer sweat glands, leading to dryness, thickening, and reduced elasticity, which can cause the skin to crack under pressure. Other causes include excessive standing, obesity, wearing open-back or ill-fitting shoes, aging skin, and various medical conditions such as athlete's foot, eczema, psoriasis, diabetes, and thyroid disorders. Nutritional deficiencies such as lack of vitamins B3, A, C, E, and minerals like zinc can also contribute to cracked heels. Additionally, environmental factors like cold weather, exposure to water that strips natural oils, and poor foot hygiene play a role in the development of this condition.