What are calluses and corns?
Corns are extremely common and can be exquisitely painful, but what are calluses and corns on the foot? How are calluses and corns treated? This segment will explore corns, why corns develop and what to do about them.
Connie had pain on the bottom of the foot for several months and it was becoming more and more disturbing. The lump in her skin on the sole of the foot had become more like a little horn. Now it felt like she was walking on a little rock, especially when she was barefoot. The pain radiated up into her toe. She had picked the horn off before, which made it feel better, but it seemed to grow back within a few days.
Corns are special calluses that develop on the feet. They can occur on the side of the toes, on the sole of the feet and in between the toes. Unlike calluses that may develop on the hands and peel off, corns grown into the skin, displacing the normal tissue, until the weight from the bone is applied nearly directly to this hard thickened skin.
The skin of the foot is a complex structure that is specially designed for its job. This job is to cushion and spread out the pressure from the bones to the sole of the foot. This skin is called glaborous skin. The skin of the bottom of the foot is much thicker than the skin in other places. In addition, like the air pockets within the sole of a pair of running shoes, the fat on the bottom of the sole of the foot is divided into compartments. When these compartments are pressurized by weight, they do an excellent job of dispersing weight, of keeping one part of the skin from taking on the pressure.
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What does a corn feel like?
A corn is usually very painful. Corns can develop along the tops and sides of the joints of the toe especially along the edge of the fifth toe. They can develop in between toes when one of the bones of the toe rubs on the bone of the toe next to it and on the sole of the foot, usually near the ball of the foot. A corn feels like walking on a little stone. Sometimes, some of the corn can be picked out, which helps until it recurs.
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Why do calluses and corns occur?
The skin of the foot is a complex structure that is specially designed for its job. This job is to cushion and spread out the pressure from the bones to the sole of the foot. This skin is called glaborous skin. The skin of the bottom of the foot is much thicker than the skin in other places. In addition, like the air pockets within the sole of a pair of running shoes, the fat on the bottom of the sole of the foot is divided into compartments. When these compartments are pressurized by weight, they do an excellent job of dispersing weight, of keeping one part of the skin from taking on the pressure. A corn develops when this structure is disturbed in one or more ways.
- Age. Age can thin the skin, deflating these fatty compartments. The same thinning of the skin that occurs on the arm, occurs in the sole of the foot. This disturbs the weight dispersing function of the skin in the same way that letting the air out of your car tires, driving on the rims would.
- Disuse. Have you ever shaken the hand of a man who does heavy manual labor for a living? They are thick. Right? Well, like a muscle, the skin of the foot (and hands) responds to its environment and thickens and toughens. However, we go to great lengths to protect our skin and feet from the normal stresses that keep it healthy by wearing “supportive shoes” and arch supports.
- Injury. Both through trauma and deterioration. There are ligaments under the joints of the ball of the foot and heel that transfer weight. These ligaments are slightly different that the ligaments of the knee or hip in that they are both capable of being ligaments (controlling the motion of the joints and positioning the arch and toes) and capable of transferring the weight of the body through the bones into the fat of the skin. While these differences adapt them to this very unusual job, it also makes them less able to repair themselves. This is why hammertoes develop. When the ligaments tear, the bones penetrate them, concentrating pressure on the skin, leading to corns. In addition, corns can develop around the hammertoes because of the shift in their position.
- Shoe wear. Shoe wear can also cause corns to develop. Pressure from the shoe with a toe box that is too tight can rub on the tops and sides of the foot resulting in corns. The most subtle, though, it that the shoe can push the thick (glaborous) specialized skin to the center of the foot, and away from the toes on the border of the foot (the first and fifth toes). The thinner skin is less able to transfer the weight and develops these calluses.
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The evaluation of Corns.
Although there are less likely, but more dangerous possibilities, the main thing that can be confused with a corn is a wart. A wart is caused by a virus. A corn is caused by pressure. There are a couple of clues to telling the difference between a wart and a corn. Warts tend to be in multiple places. Corns tend to be in specific areas of direct pressure from the bones. Corns are usually 1-5 mm in size and are usually oval or round in shape. Warts can be larger and are sometimes irregular in shape. The most telling is that when they are pared with a knife or scalpel, there will be small black specks in a wart. A callus will be yellow and translucent without specks.
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The treatment of Corns.
The first step in treating corns is to reduce the size and depth of the corn. This takes away the “I feel like I’m constantly walking on a pebble” feeling. It also allow the normal, protective fat to resume its place, protecting the bones. This should be done gradually and consistently. A pumice stone is the safest way to do this and several products are available. However, it can take a long time. If you are careful and your eyesight and flexibility are good, the callus can be pared with a special blade that acts like a planer for wood, peeling away the layers of skin. Do not dig into the depths of the corn and do not aggressively try to get it all at once or you will make it bleed. Patience is key. After repeated and gentle parings, the corn will gradually go away.
Second step is to correct the problem causing the corn. The thinning of the skin that occurs with age and disuse can be reversed by gradually spending less and less time in shoes. The operative word, though, is gradual. If you suddenly take your feet from a protected environment to doing all activity barefoot, its like taking a couch potato and throwing him into boot camp. You’re going to get a stress injury. Make a plan for a gradual increase in activity from shoe protection to some barefoot actitiy over weeks and months. Let pain be your guide. A little is ok, but if the pain is more than minor or is increasing, back away from this activity.
Selection and modification of shoe wear is also helpful. When you wear shoes, ensure that the toe box is wide and high enough so that the toes do not rub on it. A shoe stretcher can aid in maintaining the volume of the toe box and small peg can be attached to the stretcher to widen certain areas that push directly on the corn. If the corn occurs on the sides of the forefoot sole, ensure that the liner is not cupped on the edge pushing the thick skin toward the center. Sometime a metatarsal pad can be used to help this. However, comfortably positioning these pads sometimes takes some trial and error. Corns that occur in between toes can be protected with a separating pad.
Unfortunately, once toe deformities occur, it is not possible to reverse them without surgery. However, making sure that the shoes accommodate these deformities, that the calluses are kept pared down, and using protective pads can often keep you off of the operating table.
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Surgery for Corns
Most surgery for corns involves removing the deformities and injuries that cause the boney prominences that cause the corns and should be reserved for situations that do not respond to consistent efforts at treating the corn non-operatively.
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