calluses are a thickening of the outer layer of the skin. Corns occur over joints on the tops or sides of the toes. Calluses usually occur at the tips or bottoms of the toes and feet, as well at the heels. Corns tend to
be smaller, calluses more diffuse.
In most cases, corns and calluses are caused by abnormally high pressure or friction on the skin over a bony prominence, when pressed against the shoe, or another bony part of
the foot, such as one toe against an adjacent toe. The formation of the corn or callus is a protective response of the skin to these stresses. Unfortunately, as corns or calluses thicken, pressure at the area
consequently increases. A cycle of increased pressure and increased callus or corn formation may ensue.
When mild, the corn or callus may appear as a barely discernible thickening of the skin, with reddening of the
skin beneath or around it. Burning or aching pain may be present, and may seem disproportionally high in relation to the skin changes.
When moderate, the skin will be notably thickened. There may be fluid deep to the
skin, which can be felt through the skin (a bursa), which is one of the ways the body tries to protect the area from the abnormal forces acting on the skin. This can be quite painful.
With increased forces, the corn
or callus may have dry, dark splintering within it. The is caused by bleeding within the lesion.
In cases in which the pressure and friction exceed the ability of the skin to thicken, the skin may break down to
form an open sore (ulcer). There can be tendon or bone visible through the sore. The risk of infection to the soft tissues or bone are sharply increased in these instances.
A clinical examination
reveals the presence of the skin changes listed above. Differentiating corns and calluses from other lesions which cause thickened skin, such as warts, occurs. X-rays may be used to pinpoint underlying bony problems
which cause the corns or calluses. Should infection be suspected in the presence of an open sore, specimen may be taken in order to identify any infecting organisms.
Non-surgical treatments for
corns and calluses entail reduction of the thickened tissue. It may be advisable to change your footwear to shoes which have more room around any bony prominences. Cushioning insoles are used to provide reduction of
pressure on the bottoms of the feet. Foot powders may be prescribed when the feet remain abnormally moist; by decreasing the moisture, skin friction is also decreased. Function foot orthoses (orthotics) are commonly
prescribed if abnormal foot mechanics is causative of increased shear. Padding of various sorts can provide marked pressure and pain relief.
Surgical treatments are used to decrease pressure and friction by reducing
prominences, correcting deformities such as hammertoes or bunions, and to correct abnormal foot mechanics.