What are calluses?

Calluses on the foot are areas of hard, thickened skin. When the skin gets hard and thickened in certain areas, it tends to take on a yellowish appearance. Calluses are usually found over the areas of the foot that rub on things, causing a chronic mechanical injury. The skin reacts to this by thickening – it does this as a form of protection. If the skin stayed thin, it might be damaged – by thickening it adds a protective layer of skin over the area.

Calluses tend to be found in the areas of the foot where the skin rubs between a bony prominence on the inside and footwear on the outside. Apart from the rubbing of the foot on footwear, there can also be mechanical stresses in “foot to ground” contact and also “toe on toe” rubbing.

Corns and calluses may be a sign of abnormal foot function. They can be caused by abnormally high stresses and loads being put through that area of the foot. This irritates the skin, causing it to thicken – and hence the callus or corn appears.

The common areas to get calluses are:

• the weight bearing areas of the foot (ball and heel)


• over the bony prominences on the inner and outer edges of the foot


• over the toe joints


• on the tips of the toes


• between the toes

What are corns?

Corns are basically the same as calluses but with an extra feature. Calluses are called corns when the centre becomes hardened – this central area being harder to the touch than the rest of the callus. This central hardened area occurs at the point where most of the pressure that is causing the corn to be formed has been focused.

Sometimes it looks the same colour as the rest of the corn and therefore in these situation, can only identified by touching. In some corns the central area can be white or some other discoloration may be seen.

What different sorts of corns are there?

There are different sorts of corns. The commonest ones found are called:

• hard corns


• soft corns


• seed corns

Hard corns

Hard corns are formed in areas where mechanical pressure and stresses has been focused on the skin, causing the classic sort of corn that is described above.

Soft corns

Just as the name suggests, soft corns are softer to the touch than hard corns. They are found between the toes, usually in the gap between the fourth and fifth toes. They are started by the same pressure or mechanical stresses that causes the skin to go hard, just like the hard corns. Then moisture from sweat collects and macerates the skin, making the thickened hard skin go softer and turn white.

Soft corns are often be quite a bright white colour, and as it is found between the toes, it is often confused with athletes foot which is a fungal infection.

Seed corns

These slightly stranger corns look like a their name, like little seeds, on the skin of the foot. They are found around the edges of weight bearing areas of the foot. They are usually found by themselves, although they can occur in clusters. They are more commonly found in people with dry skin – a condition called “anhidrosis”.

Less common corns

There are sub-ungal corns, which are corns found beneath the nails, on the nail bed. There are also fibrous corns and vascular corns. An expert podiatrist will be able to identify these rarer sorts.

Foot function

Before thinking of treating the callus or corn, a podiatrist will assess the foot to try to identify why the callus or corn has been formed in the first place. This may be something simple, such as badly fitting shoes, but it may also indicate abnormal function of the foot during the walking process. This can be addressed in several different ways depending on the findings.

Treatment for corns and calluses

Why treat corns and calluses?

Corns and calluses on feet are painful. This might range from a little discomfort to quite severe pain. This pain is caused by pressure on the soft underlying tissue which is under the corn or callus. The pressure or rubbing that has caused the corn or callus pushes on the hardened tissue – and this is transmitted through to the soft tissue and pin or discomfort is felt.

Podiatrists and Chiropodists treat corns and calluses to remove this pain or discomfort.

Principles of Treatment for Calluses and Corns on Feet

As the pain or discomfort is caused by the mass of hardened tissue being pressed into the soft underlying part of the foot, the best way to treat Corns and calluses on feet is to remove both:

• the cause of the pressure


• the mass of hardened tissue

whilst causing as little damage to healthy tissue as possible.

The underlying causes

For successful treatment of calluses and corns on feet, one of the most important factors is to identify what has caused it in the first place. It is essential to remove the cause of rubbing or pressure prior to removal of the corn or callous. There are two reasons for this.

Firstly as the corn or callus has been caused by this pressure or rubbing, any good from treatment will be immediately undone if the underlying cause is not removed.

Secondly, the corn or callus only formed in the first place to try and protect the underlying tissue from the rubbing or pressure. Therefore if your podiatrist or chiropodist removes this protective layer, but does not also remove the cause, the soft underlying tissue would be exposed to the damaging effects of the pressure or rubbing directly onto soft and healthy tissue.

Treatment of a Callus

A callus is a thickened mass of dead skin, that is caused by pressure or rubbing over a part of the foot or toes. This pressure is created by a bony prominence on the inside of foot rubbing against something else on the outside of the foot – such as ill fitting footwear or another toe.

The layers of dead skin that make up the callus, are discoloured – usually a yellow in colour. An expert podiatrist or chiropodist is able to remove this in very thin slices with a scalpel, ensuring that the callus is completely removed, without damaging the underlying healthy tissue.

Although this may sound painful, it is not – provided the healthy tissue is left completely alone. Hence the need for an expert!

The reason the removal of calluses do not hurt the patient is that there are no nerve cells in the thickened, dead layers of skin that make up the callus. Therefore, when these layers are carefully peeled away with a scalpel, it is really only cutting through dead protein – just like cutting nails or hair.

As the podiatrist or chiropodist is only removing dead tissue, there should be no bleeding whatsoever nor risk of infection.

Usually, only one treatment is needed. Patients are usually asked to return after 6 to 8 weeks to ensure that the area is healing healthily and that there are no signs of recurrence. Occasionally, a callus can be extensive and might need more than one treatment episode. In addition, if the underlying cause has not been adequately treated, there may be signs at the follow-up that the callus is coming back and so further treatment can be advised.

Treatment of Corns

Treatment of hard corns

The treatment of hard corn is virtually identical as that for calluses – with one exception. As a hard corn is actually a callus but with a deep hard centre, once the callus part has been removed, the centre needs to be cut out. This is called “enucleation” of the centre.

Removal, or enucleation, of the centre will leave a dimple or hole in the tissue of the foot. In time, with healing, the body will naturally fill this up with healthy tissue. However, whilst the healing process is occurring, the cavity is usually filled with a gel (polymer, silicon or acrilyic) which discourages further corn formation.

As with the treatment of calluses, the treatment of corns is often limited to one episode only. However, if the corn is large, in a difficult area or has been there for years (ie: is a chronic corn), there may need further treatments to get resolution. A podiatrist or chiropodist will be able to decide this at the 6 – 8 weeks review.

Treatment of soft corns

Treatment of soft corns requires removal of the dead tissue with a scalpel – just like hard corns. However, as the skin is not hard but “macerated” by fluid, the white soft tissue can be separated from healthy tissue with care.

As sweat collects between the toes, and the toes rub against each other to cause the corns, there is often need for a toe separator. This is a device that holds the toes apart – allowing sweat to evaporate and to stop the toes rubbing together.

As part of the treatment, a podiatrist or chiropodist will suggest that the patient pays special attention to careful cleaning and drying of the toes and the web spaces between them. In addition, surgical spirit (which is alcohol) can be used on soft corns. Surgical spirit, when it is put on the skin and allowed to evaporate, dries out the skin cells as well as sterilising the area.

Treatment of seed corns

Seed corns are associated with dry skin (anhidrosis)

Treatment of these is based upon removal of the little corns themselves and and then application of an emollient – often containing Urea cream. An emollient cream is one that keeps the water in the skin, keeping it well moisturised and preventing it from drying out.

As seed corns are usually multiple, it is usual to review patients in 3 months after treatment, to see if there is any need for further treatment.

Treatment of subungual corns (corns situated under the nails)

Corns that occur under the toe nails (subungual corns) are very difficult to treat. It is impossible to get to the corn with the nail still in place. Therefore to get to the corn in order to treat it, the nail needs to be removed. Usually a podiatrist or chiropodist will only need to cut back the nail sufficiently to expose the corn. However, in some cases, the whole nail might have to be removed.

Once the nail has been cut back or removed, the corn can be removed with scalpel. As it is so important not to get the corn back again, in most cases a caustic agent such as silver nitrate can be used to destroy the corn tissue. If the corn can be eradicated, then it may not be necessary to remove the nail again.

With subungual corns, it is important to review the patients every 2-3 weeks to check nail is growing back healthily and with no recurrence of the corn.

Treatment of neurovascular corns

Neurovascular corns are corns that have both nerves and blood vessels in them. As most corns have only dead tissue in them, this makes neurovascular corns more difficult to treat. Firstly they are sensitive and can be painful to treat and secondly they can bleed if removed. As such, podiatrists and chiropodists usually remove these under local anaesthetic.

Neurovascular corns need extensive excision to get rid of them and bleeding may occur. A caustic such as silver nitrate can be used to help to destroy the corn tissue. They often recur and need further treatment is often needed. Fortunately they are rare.

Patients are followed up and reviewed at 6 – 8 weeks to see if further treatment is needed – unless silver nitrate is used in which case the patient needs to reviewed weekly.

Conclusion

With expert treatment most calluses and corns on feet can be adequately managed, and have a possibility of eradicating them completely.