Anhidrosis is the term used to describe dry feet, some people suffer from an unusually dry skin that leaves the skin, flakey, peeling and thin. Some parts of the foot may thicken and crack. The heels are particularly prone to cracking which leads to fissures. These can be deep and bleed when they split.
Not all thick skin on the heels are Dry skin, so in order to distinguish dry skin from callus by observing the texture of the skin on other parts of the foot like the arch. Anhidrosis (dry Skin) is dry on top of the foot as well, and may appear up the legs and on the hands.
Calluses however are sites of pressure and shearing due to footwear or biomechanical problems. However at times they do exist in combination. Dry skin may have its root in skin conditions like Tinea Pedis (athletes foot), or Eczema.
Applying emollients or moisturising creams to the foot, may make a difference if done on a regular basis, and certainly some creams are more effective than others. Those that do not appear to respond to creams may have un underlying Fungal Infection, that appears as dry skin, throughout the bottom of the feet, with a hint of redness. These will require a different approach to treatment. Other reasons for dryness may be due to diabetes, poor circulation and nutritional deficiency.
Emmolients that have urea in them, are more effective in assisting the cells in moisture retention.
Certain skins are sensitive to soap, and may respond better to products that act as cleansing agents.
Your podiatrist may help you identify the reasons behind you anhidrosis/dry skin problem.