Our bodies are remarkable at adapting to all sorts of stressors. When a muscle, tendon or bone is placed under regular strain, over time it will make itself bigger and stronger to deal with future physical loads. The skin is no different, for it too is a living and adaptable structure.
When an area of skin is repeatedly rubbed over time, its top layer thickens and toughens up to protect the more delicate layers below. In response to this shearing force, the skin forms a diffuse area of thickened skin called a callus. You may have observed this happen to the palms of your hands, after a prolonged period of using tools or digging in the garden.
Callus is also common on the feet, in fact probably more so. However, you may not be aware of callus because it is frequently out of sight. Often, the first thing to alert you to its presence is pain. This occurs when the build-up of hard skin starts to place pressure on the nerve endings beneath it.
Callus on the feet occur where skin is sheared against the ground or footwear. Typical sites are on the balls of the feet and inner aspect of the first toe. Heel callus is also common and is due to repeated bulging of the fat pad from under the heel bone. When the callus around the heel is allowed to stretch and move (as occurs when in bare feet or thongs) it can crack, exposing the viable deeper layers of skin. This can be very painful.
As mentioned, callus formation is part of the body’s natural protective response to skin stress. But when pain develops as a result of it, then it becomes time to remove it. Unfortunately, not everyone can feel the damage that the callus may be doing. People with loss of sensation in their feet, such as those with diabetes, may not be aware of this and the consequences can be severe. Left unmanaged, callus compresses the tiny blood vessels close to the skin. When blood flow is cut off, the skin breaks down. It is not uncommon to remove the callus from a diabetic’s foot only to reveal an ulcer beneath it.
Treatment of callus involves debriding it with a sterile blade. A podiatrist is a health professional skilled at doing this and it is a painless procedure. Your podiatrist will also be able to identify how your foot function and footwear is contributing to callus formation, and offer advice as to slow or prevent its recurrence.