[image:image-1]Corns and callous are one of the most common problems seen by Podiatrists.
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Corns and callouses are forms of hyperkeratosis, (thickening), of the epidermal, (top), layer of the skin, be it any where on the body, but generally on the hands and feet, in response to continual or intermittent trauma, pressure or friction, (rubbing).
The symptoms can vary from a mild burning sensation to an infected ulceration, typically under a corn on a toe.
The formation of thickened skin is a natural and normal way for the skin to react. The skin is reacting to excess pressure on an area that is unable to withstand that amount of force and is thickening to prevent wear & tear in the same way as we place patches on the knees of trousers and elbows of jackets to thicken the material.
A corn and callous should be regarded as an indication of another problem that is present rather than a condition in their own right.
[image:image-2]WHAT ARE CORNS?
The name "corn" comes from its appearance under the microscope. The hard part at the centre of the corn resembles a barley hare. Corn used to be a generic term for grain, and the name stuck. The scientific name is helloma, (plural hellomata).
A corn is a small, concentrated area of hard skin, usually in hairless and smooth skin that typically develops over a bony prominence, such as the apex of the toe, the top of the toe or between the toes. Because the pressure on the skin is greater over this area the cells of the skin are more compressed and become harder in structure. Corns are typically conical in shape with the base of the cone on the surface and the point of the cone deeper in the skin affecting deeper nerve endings, hence the intense pain of a corn. The conical shape follows the lines of pressure onto the skin where, typically, pressure starts from a wide angle down to a narrow point onto the bone.
There are five different types of corns. The two most common are hard and soft corns.
HARD CORNS, (helloma durum).
These are the most common and appear as concentrated areas of hard skin usually within a
wider area of thickened skin or callous, and can be symptoms of feet or toes not functioning
properly. They commonly occur on the top of the smaller toes or on the outer side of the little
toe. These are the areas where poorly fitted shoes tend to rub most or bad foot function can
cause excessive pressure.
SOFT CORNS, (helloma molle).
These develop in a similar way to hard corns; they are whitish and rubbery in texture where the skin becomes soft & moist from sweat that is unable to evaporate, or from inadequate drying, commonly between the 4th & 5th toes. They always appear between toes over one of the inter-phalangeal joints. In a good foot the joints in adjoining toes are staggered so when toes rub together there is no direct, excessive pressure over the bones, so the skin does not need to thicken to protect itself. This relationship is altered in deformed toes or a foot that over pronates.
These are tiny corns that tend to occur either singly or in clusters on the bottom of the foot, commonly under the 2nd metatarsal shaft or under the heel. They seem to be associated with friction and a dry skin. They can be usually painless. They can sometimes be "picked" out after a bath when the skin is soft.
These corns will bleed profusely if they are cut and can be very painful. They can be caused from a hard corn that is badly treated over a long period of time or where the pressure has been excessive without treatment for a long period and the skin structure has changed. They can sometimes be confused with verrucae.
These arise from corns that have been present for a long time. They appear to be more firmly attached to the deeper tissues than any other corn. They may also be painful.