Foot Corns & Callus (hyperkeratosis)
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
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.
Chilblains (Pernio; perniosis)
What are chilblains (pernio; perniosis):
Chilblains are a painful abnormal reaction of the small blood vessels in the skin when exposed to cold temperatures. Chilblains usually occur several hours after exposure to the cold in temperate humid climates. The cold causes constriction of the small blood vessels in the skin and if rewarming of the skin happens too rapidly, there is leakage of blood into the tissues as the blood vessels do not respond quickly enough to this rewarming. Chilblains are not very common in countries where the cold is more extreme as the air is drier. The living conditions and clothing used in these climates are protective. Chilblains are more likely to develop in those with poor circulation, but chilblains are still common in those with good circulation.
What do chilblains look and feel like:
Chilblains appear as small itchy, red areas on the skin. Chilblains become increasingly painful as they get congested and take on a dark blue appearance. They may also become swollen. As they dry out, chilblains leave cracks in the skin so the risk of getting an infection increases. Chilblains are common on the toes, but can also affect the fingers and the face (especially the nose and ears). Chilblains are also common on areas of the feet exposed to pressure, such as bunions or where the toes are under pressure from tight shoes or where there are corns and callus.
Chilblains start during the winter (when the weather gets colder) – the initial symptoms include burning and itching in the area of the developing chilblain. These symptoms are often intensified when going into a warm room. There is often some swelling and redness. In many cases, the skin over the chilblain can break down and becomes a sore (ulcer). An infection may develop in the chilblain.
Chilblains often occur in some people every year, for the rest of their lives. In other’s, chilblains occur for several years and then just stop occurring. The reason for these patterns of occurrence of chilblains is not known. As they are more common in females, there may be a hormonal influence on the development of chilblains.
What causes chilblains:
Chilblains are more common in those that are just more susceptible to them – the reasons for this are not entirely clear. Factors that contribute to tendency to chilblains include, a familial tendency, poor circulation, anemia, poor nutrition, hormonal changes, some connective tissue disorders and some bone marrow disorders. Damp living conditions may also increase the risk for chilblains.
As a chilblain is an abnormal reaction to cold, these factors above increase the risk that it is going to happen. Chilblains occur when there is too rapid a change from cold to hot, so the chilblains occur after the foot is cold. Some people’s circulation is so sensitive that only small changes in temperature may be enough. A typical history for the development of chilblains is after being outside in the cold, the foot is placed next to a heat source (eg heater) when coming back inside. The small blood vessels do not respond quickly enough to the change in temperature
Chilblains self treatment:
Prevention of chilblains:
Keeping your feet warm is an important way to prevent chilblains – use trousers, high top boots, tights, leg warmers and long, thick woollen socks. If your feet do get cold, allow them to warm up slowly – do not put them straight in front of a source of heat (this gives a chance for the circulation to respond to the warming skin). Do not let the feet become exposed to any source of direct heat (eg a heater), especially if the foot is very cold – this is a common factor causing chilblains. Smoking also interferes with the circulation in the small blood vessels and increases the risk of getting chilblains.
Once a chilblain develops:
* do not rub or scratch chilblains
* avoid direct heat (ie do not expose the feet to a heater), but keep the feet warm by the use of woollen socks and footwear
* use soothing lotions (eg calamine lotion)
* if the skin is broken, use an antiseptic dressing to prevent the chilblains becoming infected
* those with diabetes or poor circulation should see a Podiatrist. The risk of further complications from the chilblains in those with a foot that is ‘at risk’ is too high to delay seeking professional help
* thermal or insulating insoles can help keep the foot warm to prevent chilblains
* lanolin or a similar lotion that is rubbed into the feet will help stimulate the circulation
* there are a number of natural or homeopathic remedies that are recommended for the treatment of chilblains. Some of these do appear to help some people.
Podiatric management of chilblains:
Podiatrists see a lot of people with chilblains in cold humid climates and can give advice beyond what is listed above:
* padding and pressure relief may give some relief for the chilblain symptoms
* topical steroids may need to be used in case of very swollen severe chilblains
* corns and callus are common in the pressure areas where chilblains can occur, so reduction of these will give some pain relief
* heparin ointment may be used in some people to improve the circulation in the area
* a course of UV light at the start of winter in those prone to chilblains has been recommended to help stimulate the circulation in the foot
* a very rare occasions the chilblains may be a symptom of rare medical problems (eg connective tissue disease or a bone marrow disorder)