What is a callus?
A callus is a thickening of the skin as a reaction to friction and pressure. They can develop anywhere that the skin is receiving repeated trauma that is below the level needed to cause full tissue failure (a sore/wound). Normally calluses are found on the soles of the feet and palms of the hands but they are by no means limited to these areas.

Why should I be concerned about my callus?
In the short run calluses can be a good thing. They help to protect the underlying skin from injury. The problem starts when the event causing the callus is not fixed.

For example: a pair of shoes that do not have good support along the arch. This can cause the ball of the foot to rub in the shoe. This is far below the amount needed to cause a wound but the friction and the pressure from the body will start to cause a callus over time. If the callus is found and the shoes are replaced with a more supportive pair, no problem, but if the shoes are not replaced then the callus will continue to form.

Eventually this callus will become too hard and thick to be protective. It can cause the very thing it is trying to prevent. When the callus becomes too large and hard, it becomes a source of trauma and can proceed to damage the skin under the callus. This can lead to an open wound that can quickly become very large and deep.

While this process is most common in diabetic patients that have lost the feeling in their feet, anyone with decreased sensation in the area of the callus is at risk. Most patients with feeling in the area of the callus will become irritated with the callus and have it removed by the time it is damaging the skin. Keep in mind that a callus does not have sensation, but the skin around and under it may.

How and when to treat a callus:
A callus is a sign of a problem, so in some way, every callus needs to be treated. If it is a small and thin callus, finding the cause and correcting it will normally do the trick. A harder callus may need the use of creams or soaking to soften it and then be removed with an abrasive device (Pumice stones, emery boards, etc).

For those that can feel the area of the callus, there are a lot of over-the-counter products that can help (Kerasol, foot lotions, etc.), for those without sensation, avoid creams with salicylic acid as this may cause damage to the healthy skin. Instead, use creams with urea of at least 20% (Kerasol 20, Heel balm). I do not recommend using the devices that look like cheese graters or razor blades to remove calluses regardless of sensation. It is just too easy to damage the skin with these and most calluses are in positions that are hard to work on by yourself.

If you have a callus that is large, hard, or discolored, then I suggest professional help (Physician, Podiatrist, or Physical Therapist with wound care knowledge). These types of calluses can be hiding a sore under them that will need treatment. Also at this stage the callus is very hard and time consuming to remove on your own and the professional can remove it quickly and safely with debridement. Regardless of the method used to remove the callus, the cause of the callus still needs to be fixed or the callus will return.