Diseases of the Foot
A callus (or callous) is an especially toughened area of skin which has become relatively thick and hard as a response to repeated contact or pressure. Since repeated contact is required, calluses are most often found on hands or feet. Calluses are generally not harmful, but may sometimes lead to other problems, such as infection. Shoes that fit tightly can often produce calluses on the feet.
People with diabetes face special skin challenges. Because diabetes affects the capillaries, the small vessels which feed the skin its blood supply, thickening of the skin increases the difficulty to supply nutrients to the skin. Additionally, the shear and pressure forces that cause corns and calluses may tear the capillaries, causing bleeding within the callus or corn.
Often, bleeding within the calluses is an early sign of diabetes, even before elevated blood sugars. Although the bleeding can be small, sometimes small pools of blood or hematoma are formed. The blood itself is an irritant, a foreign body within the callus that makes the area burn or itch. If the pool of blood is exposed to the outside, infection may follow. Infection may lead to ulceration. Luckily, this process can be prevented at several places, but such infections can become life-threatening. Diabetic foot infections are the leading cause of diabetic limb amputation.
A common method, often done by a podiatrist, is to shave the calluses down, and perhaps pad them.
The most basic treatment is to put a friction-reducing insole or material into the shoe, or against the foot. In some cases, this will reduce the painfulness without actually making the callus go away. In many situations, a change in the function of the foot by use of an orthotic device is required. This reduces friction and pressure, allowing the skin to rest and to stop forming protective skin coverings. At other times, surgical correction of the pressure is needed.