Fish scale hard skin on the heel may be caused by ichthyosis, palmoplantar keratosis, chapped hands and feet. 1. Ichthyosis: is a class of dry skin with fish scale scales as the characteristics of keratinization abnormal skin disease. Its main manifestations are dry skin in winter, scaling of the skin surface, keratinization of the palms and toes, abnormal nail development, abnormal eyelid closure, corneal pitting turbidity and other symptoms. This can cause ichthyosclerosis on the heels. 2. Palmoplantar keratosis: it is a hereditary skin disease characterized by diffuse or limited hyperkeratosis of the palms and toes, which is mainly manifested as roughness of the skin of the palms and toes, thickened plaques and other symptoms, and some of the people may be accompanied by peeling and other symptoms. It may also lead to ichthyosiform hard skin on the heels. 3. Cracked hands and feet: it is a disease of rough, dry and cracked skin of hands and feet caused by various reasons. Its main manifestations are cracked palms and soles, dry, rough, painful and bleeding skin. It can also lead to ichthyosis on the heels. There are many other causes of ichthyosclerosis on heels such as keratosis pilaris and chronic eczema, which should be taken seriously, and the cause should be identified in time, and further treatment or therapy should be prescribed by the doctor.