What is a corn and callus?
Corns and callus are one of the most common problems seen by Podiatrists. They can occur on any part of the foot and vary in symptoms from a mild callus under the foot, to an infected ulcer that can develop under a corn on a toe. Other names for corns and callus are hyperkeratosis, clavus, heloma and tyloma).
Pathologically they are all the same - the skin has thickened in response to pressure. A callus generally refers to a more diffuse thickening of the skin (more common on the toes, but can occur under the ball of the foot) whereas a corn is a thicker more focal area area (more common on the toes). A corn can occur under and be surrounded by callus.
What is a foot corn and callus (hyperkeratosis):
A corn or callus are areas of thickened skin that occur in areas of pressure. They are actually a normal and natural way for the body to protect itself. For example, callus develops on the hand when chopping a lot of wood - its a normal way for the skin to protect itself. In the foot, the skin will thicken up to protect itself when there are areas of high pressure. The problem occurs when the pressure continues, so the skin gets thicker. It eventually becomes painful and is treated as something foreign by the body.
What does a foot corn and foot callus look like:
Corns appear as a horny thickening of the skin on the toes. This thickening appears as a cone shaped mass pointing down into the skin. Hard corns are usually located on the outer surface of the little toe or on the upper surface of the other toes, but can occur between the toes. A soft corn occurs between the toes and are kept soft by the moisture in this area. A callus is more diffuse area of thickening and does not have the focal point of the corn.
What causes foot corns and callus (hyperkeratosis):
Corns and callus are caused by one thing - TOO MUCH PRESSURE, usually in combination with some friction. There is no other way to get them - the pressure stimulates the skin to thicken to protect itself, but as the stimulation of the pressure continues, it becomes painful.
Too much pressure can be from causes such as:
- footwear that is too tight
- toe deformities, such as hammer toes - the top of the hammer toe is an area for increased pressure on the top of the toe
- bony prominence
- biomechanical or gait abnormalities that cause pressure under different areas of the bottom (plantar) surface of the foot (this is a common cause of callus)
As there are a whole range of problems that can result in a corn or callus, it is often good to consider that they are not really a condition at all, but are a symptom of an underlying condition.
Complications of foot corns and callus (hyperkeratosis):
Corns and callus that are not treated will become painful. They will not come right on there own unless the pressure that caused them is taken away. If it is not the skin will continue to thicken and become more painful. After a while the body will start treating it as a foreign body and a ulcer (abscess) can develop. This can get infected - the infection can spread. Infection of corns on the toe is more common than a callus. This can be a serious complication for those with poor circulation, peripheral neuropathy and the need for diabetes foot care.
What can you do to treat a foot corn and callus:
As corns and callus are symptoms of underlying problems, self treatment should follow a proper diagnosis of the underlying condition and advice on how to best manage it.
Remedies such as corn paint, cure or plasters will generally only treat the symptom of the corn and not the problem that causes it. These chemicals contain acid that are supposed to 'eat away' the corn, but the chemical can not tell what is corn and what is normal - it will eat what ever you put it on. While this can be risky in healthy people, it can be very dangerous and risky in those with poor circulation and/or diabetes. The use of "corn plasters" in those who are at risk or have frail skin are very likely to cause an ulcer (a breakdown of the skin) which could become infected and it the circulation is poor, an amputation is a possibility.
Cutting corns or calluses yourself (bathroom surgery) is not without its dangers, especially if you cut yourself. In the warm and moist environment of enclosed shoes, infection can easily develop into a serious wound.
Self treatment or management of corns and callus includes:
- following the advice of a Podiatrist
- proper fitting of footwear
- proper foot hygiene and the use of emollients to keep the skin in good condition
Podiatric treatment of a foot corn and foot callus:
Podiatric management of corns and callus include:
- a proper assessment to determine the cause of the corn and/or callus
- implementation of a management plan
The management plan is likely to take into account several options:
- regular maintenance to keep the corn and callus reduced
- use of padding to prevent the pressure
- advice about the fitting of footwear
- the use of foot orthotics or supports to relieve the pressure under the foot
- surgical correction of the bony prominence that may be causing the high pressure area
It is especially important that those with diabetes or poor circulation see a podiatrist for the management of corns and callus.
"I went to a Podiatrist, but they never took the corn out - it just keeps coming back"; "Why can't you take the corn out so it won't come back?" - corns are easy to take out - the reason they keep coming back is that the cause is still there and that cause is pressure. If the pressure is not removed, they will come back.
"My podiatrist reckons he cut the corn out, but its still sore" - there could be several reasons for this - there may be a lot of inflammation that has not yet resolved; occasionally the pain may not have actually been due to the corn or callus in the first place (for example, it could have been a bursitis or a chilblain); if the corn was severe, there could have been an ulcer or abscess that needs to heal (this can be very painful after the corn has been "removed").
Prevention of a foot corn and callus (hyperkeratosis):
Corns and callus are easy to prevent - just take away the cause and that cause is excessive pressure. No chemical applied to the corn or callus will take away pressure. Correct fitting of footwear around the toes, the use of pads to relieve pressure, surgical management of bony prominence and/or regular podiatric care are the best options for prevention of corns and callus.