Corns, calluses, hard skin: what are the differences?

Corns typically present as hard growths located on the soles of the feet or as the formation of soft skin tissue between the toes, known as heloma molle or soft corns. They usually emerge in areas subjected to repeated friction or excessive pressure. These stresses prompt the epidermal cells (keratinocytes) to increase their production of keratin in order to protect the skin, which results in its thickening.

Firstly, dead skin cells accumulate in the form of a cone. This then penetrates the deeper layers of the skin, exerting pressure on the nerve endings. Sometimes, this can lead to a feeling of discomfort or even pain.

There are two types of corns:

• Hard corns.

Quite common, they appear directly in areas exposed to pressure and friction from shoes. These are generally located on the top of the toes or on the outer part of the little toe.

• Soft corns.

They form as a result of the compression between two joints at the level of two toes and therefore occur in pairs. They are distinguished by their spongy consistency and their whitish colour.

Similar to corns, calluses represent thickened areas of the skin on the feet. They are distinguished by their extent and less defined contours. Calluses also exhibit a yellowish hue and a hard consistency. However, unlike corns, calluses do not have a hard core at the centre. These skin growths also appear in the pressure areas of the foot, and bilaterally:

• On the sides of the foot, particularly around the heel or the sole;

• Underneath the feet, at the junction between the front of the foot and the toes.

In their early stages, calluses are painless and underdeveloped. As they progress, they can form patches or cracks, splitting at the heel level. This leads to discomfort.

The term corn also refers to a thickening of the skin, this time on a broad area. Subjected to intense and regular pressures or frictions, the skin responds by thickening. It hardens and creates a sort of hemispherical outgrowth, with a crumbly roughness, which gradually yellows and can sometimes be grey in colour. In some individuals, this area becomes sensitive, even painful. The feet are generally affected due to poor ground support or unsuitable footwear.

Corns often appear on the heels, under/on the toes or under the forefoot, thus causing sharp plantar pain.

In summary, corns are characterised by hard, thick bumps with a hard core, calluses are broader thickenings of the skin without a hard core, and hard skin areas are typically caused by repeated pressure. Calluses usually have a more regular and smooth surface than hard skin areas. The latter often form in a more targeted and limited way on specific parts of the feet, such as the heels, the sides of the toes, or the joints. Compared to corns or hard skin areas, calluses tend to be less likely to cause pain, although they can cause discomfort if they become excessively thick. However, there are solutions available to alleviate these types of skin thickening.