CORNS & CALLUSES

By Ray Foster

 

This is one of a number of Medical Checkpoints giving information about common conditions and what you can do about it. Your opinion and reaction to these Medical Checkpoints would be valued and appreciated. Medical Checkpoints are published periodically by NEWSTART Healthcare and are provided as a free service.

DEFINITION

from Foot Disorders, 2nd edition, Nicholas J. Giannestras, page 427 (Calluses, Clavi and Keratoses):

Calluses are found on any portion of the forefoot where there is abnormal pressure or excessive friction.  They are formed as a defense mechanism of the skin to protect it from excessive irritation and/or blistering.  They can be found under any of the metatarsal heads, on the medial aspect of the first metatarsal head area, the lateral aspect of the fifth metatarsal head area, on the dorsal surface of a toe or toes or on the tips of the toes.

The clavus, a synonym for the corn, is found on the toes wherever there is an underlying bony prominence upon which pressure is exerted by the shoe.  The clavus is nothing more than a localized response of the skin to abnormal pressure from without against a bony prominence from within.

What is going on:

The body has an almost infinite ability to protect itself from abuse and trauma. The body functions in three different and apparently totally unrelated ways.  The body functions a) mechanically, b) chemically, and c) electrically.  The mechanical way the body protects itself to local pressure and irritation is for the skin to thicken locally.Depending on where this thickened skin is, we call it a callus (on hands or undersurface of the feet) or corns (usually on the toes).

The thickened skin is a result of increased metabolic or chemical activity within the cells of the skin resulting in thickened skin to better withstand the local stress. The electrical response to pressure and irritation mediates the pain that results. There is a combination of electrical and chemical activity that mediates the pain perception. It is the pain response that is most important in the body's protective mechanism. Without pain, the part is not rested and protected and the trauma and irritation continues until the body part is destroyed. This is what happens in diabetes with peripheral neuropathy, and in spinal cord damage and other diseases causing loss of protective skin sensation.

What to do:

1. The first thing to do is to ascertain why there is increased pressure over the place where the callous or corn is developing. There is only one way to get rid of the pain and the callous or corn - remove the pressure. Both the corn or callous and the pain are friends - friends that are trying to help us. It is the localized increase in pressure that is the enemy to be removed. There are two directions that the pressure can be relieved, inside and outside. Surgery can remove the inside half of the pressure by removing the bony prominence. Shoe modifications can remove the outside half of the pressure by making more space or softness over the bony prominence.

2. The best help in overcoming the localized pressure is determined by the cause. If the cause is pointed-toe shoes, the best remedy is to buy shoes that give more space for the toes and feet. If the cause is a deformed foot, the best help is reconstructive surgery to remedy the deformed foot or toes.

3. Palliative or symptomatic treatment is often used but never cures. What palliative or symptomatic treatment means is that something is done to make it feel better without dealing with the cause of the problem. Trimming corns or callouses is the time-honored symptomatic treatment. It does give some degree of relief until the skin grows the callous or corn back again at which time the pain and discomfort returns. The reason it feels better is that there is less pressure in proportion to the amount of callous removed. However not having removed the cause of the pressure, the same cause - the pressure - results in the same effect - the pain and callous or corn. Corn pads and soft padding has variable success to relieve the pain. The problem with padding is that it takes up space and tends to aggravate the problem because the pressure is increased in proportion to the size of padding. A corn pad is usually more successful because it shifts the site of the pressure. Getting the pressure off the bony prominence relieves the pain almost immediately. Using corn pads (doughnut shaped pads, with the hole of the "doughnut" over the bony prominence) is probably the best symptomatic treatment available other than obtaining shoes that relieve the pressure by their shape accommodating to the shape of the bony prominence. It must be realized that the symptomatic treatment must be continued indefinitely. Symptomatic treatment never cures. Symptomatic treatment is for relief that lasts only as long as the treatment is continued.

4. A word of caution: The worst kind of symptomatic treatment is to chemically alter the brain so that discomfort is not perceived. That is to say that pain pills are the worst symptomatic treatment. Special caution must also be observed in connection with callous or corn surgery on the weight-bearing surfaces of the foot. There is an unalterable law of physics that must be considered. Pressure is measured in weight per unit of surface area. Your feet carry your body weight. Your body weight is distributed over the surface area of your feet. It is not the soft parts of your feet that carry the weight, it is only your bony structures of your feet that carry the weight. Any operation that is going to remove bone from your feet is going to increase the pressure that the remaining bones of your feet must carry. For this reason careful thought should be given as to whether the surgery is going to help or make the condition worse. Think for yourself! Less bone in your foot means more pressure per unit surface area for the remaining bones in your foot. And your feet are the only feet you have!

5. Prevention: Corns and Callouses cannot always be prevented, however certain things will help:

a) Buy shoes that are as long or longer than your feet and as wide or a bit wider. It is important that your toes are not crammed together in your shoes.

b) Wear shoes and socks that give the toes room.

c) Sometimes the padding on the bottom of your feet gets thin. This may happen as you get older. Soft padding inserts in your shoes will make up for any loss of your own normal padding.   A material called "plasterzote" or "spenco" or any other of a very large variety of inserts will work well to pad your shoes. Extra-depth, or the next size larger shoes may be necessary for space.For further study: See the Medical Checkpoints entitled Plantar Warts.