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.

SEED CORNS.
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.

VASCULAR CORNS.
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.

FIBROUS CORNS.
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.
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WHAT ARE CALLOUSES?
A callous, (or callousity), is an especially toughened area of skin which has become relatively thick and hard as a response to repeated contact or pressure. As with the corn the body is protecting itself from excess wear and tear, callouses are most often found on hands or feet. Callous, the bodies natural protection, only becomes painful when it becomes too thick and this only happens when we do not wear away the skin naturally on the ground. Nature has not caught onto the fact we wear shoes to protect our skin.
Callouses are larger, broader and have a less well defined edge than a corn. These tend to form on the underside of the foot, (the sole).


What is the treatment for corns and callouses?
As the build up of hard skin is the bodies natural protection to excess wear and tear the cause of the problem needs to be addressed before nature will stop the callous building up.

TAKE AWAY THE PRESSURE AND/OR CORRECT THE FOOT FUNCTION AND THE CORN OR CALLOUS WILL NOT BUILD UP.

If you develop a painful corn or callous it is best to get expert advice from a podiatrist, (previously called chiropodist).
The kind of advice and treatments usually considered include the following.

HOME TREATMENT.

Paring down the skin.
The most common type of home treatment is regular reduction of the skin using a pumice stone or hard skin file and then using creams to keep the skin soft. This is an ongoing treatment since the cause is not usually addressed, however it enables feet to stay relatively pain free and still wear "those" shoes.

Corn Paints and Plasters.
Another treatment is the use of corn paints and plasters. These paints are a weak solution of salicylic acid that is designed to chemically burn the skin off. The plasters are just a vehicle to carry an acid ointment. Unfortunately the acid is not able to distinguish between hard skin and normal skin and the area can become inflamed, tender and can often result in ulceration. It should never be used if you have diabetes, poor circulation or on steroids.
Padding.
There are a large number of over the counter foot pads and gels now available and these are also available from the surgery. They are designed to help remove the pressure from a particular area of the foot, they cushion an area.

TREATMENT BY A PODIATRIST.
A Podiatric treatment will involve an assessment of the likely cause of the problem and a treatment plan advised.

Regular maintenance.
This could involve a regular maintenance plan where the hard skin is reduced regularly with a scalpel to keep you comfortable, pain free and allow you to wear your shoes. This reduces the thickness and therefore the pressure on the underlying tissues. The length of time before the pain returns is dependant upon many external factors but can be from 8 weeks to 6 months.

Padding/ Shoe Modifications/Shoe advice.
We can also apply padding to the affected areas to keep the pressure off a bony area, these can be temporary or a longer lasting pad can be made. Advice can also be given about various shoe modifications or shoe stretching that can be achieved to allow the foot more room inside the shoe. Sometimes a change of shoe manufacture or perhaps a little less time spent in unsuitable footwear will help.

Insoles/Orthotics.
Where the problem of corns and callous are caused by biomechanical problems in the gait cycle then an insole or orthotic is the best long term option as this corrects the function of the foot so that the gait cycle is in harmony with the rest of the body. This reduces the conflict that the foot has with the shoe during walking and can lead to a more comfortable walk and reduced callous and corm build up.

Surgery.
In some cases, usually toe deformities, surgery is usually the best long term option, especially where a hammer toe can be straightened, to reduce the pressure from the shoe. Whilst this is a very successful treatment not everyone likes the idea of foot surgery. This type of treatment is best carried out by a Podiatric Surgeon, usually privately, but is sometimes available on the NHS.

© Burchell & Associates 2008