Besides corns, the hard bumps on your feet could also be this, and it's contagious!

In our busy lives, our feet carry us around every corner, and it is inevitable that they will have some problems. Some problems are not easy to find, but there is a common problem that troubles many people, that is - corns.

Many people notice corns on their feet. They suddenly discover a lump on their toes that is not only hard but also painful, especially when squeezed while walking.

So, what exactly are corns? How are they formed? And how can they be prevented and treated? This article will take you to find out.

What are corns?

The reason why it is called corns is simply because this bump on the surface of the skin looks like a corn in shape.

Image source: Wikipedia

As can be seen from the picture, the basic characteristic of corns is the local thickening of the skin's stratum corneum, which looks like a round pimple or small lump.

In addition, this type of cornification has some characteristics, that is, the central part is harder and the surrounding part is softer, and it may look a little inflamed. Corns are generally painful when squeezed or touched (including walking and wearing shoes). This pain is caused by the central core of the corn compressing the underlying nerve structure.

What causes corns?

The cause of corns is simple: friction. Specifically, it is a chronic skin reaction caused by repeated, long-term friction or pressure.

It can be seen that the formation of corns is a gradual process. At the beginning, it may be just a slight thickening of the skin. Over time, local pressure and friction will cause the stratum corneum of the skin in this area to thicken further, eventually forming a hard cone-shaped protrusion in the center, accompanied by pain.

A characteristic feature of corns is that they are more likely to grow on the feet, especially on the toes and soles, which are common points of stress and prone to friction.

Regarding the location of the attack, it must be mentioned that corns can be divided into 2 types:

Hard corns: These usually appear on the soles of the feet and on top of the toes. They have a harder cuticle, especially in the center.

Soft corns: They often appear between the toes. Because the area between the toes is moist and the stratum corneum is relatively soft, they may still cause significant pain and discomfort.

Although the two may look and feel different, they are essentially the same thing - pressure and friction on the skin. In addition, the common causes of corns are:

· Shoes that do not fit: For example, the shoes are too tight or too small, which always squeeze the feet; for example, the toe box or sole is too hard, which always causes the feet to rub against the shoes; for example, often wearing shoes with heels transfers the pressure of the feet to the toes, increasing the friction and pressure on the toes.

Activity patterns: If you stand, walk, or run for a long time during work, life, or leisure time, that is, if you use your feet for a long time, the skin on the soles of your feet or toes will be under excessive pressure, which will increase the risk of corns.

Abnormal bone structure of the foot: If the structure of the foot is not normal, such as toe deformity and incorrect walking posture, some parts of the foot will be stressed more unreasonably, and after frequent pressure, the risk of corns may increase.

· Aging: As we age, the epidermis changes, causing the protective layer to become thinner and dryer, which may contribute to the relatively higher incidence of corns in the elderly.

Based on the above, it is not difficult to understand that some people are more likely to develop corns. We roughly summarize them in the table below for reference.

Table 1. People who are prone to corns

What problems are easily misdiagnosed as corns?

For the general public, corns may be confused with other similar diseases. Calluses: The most common situation may be that calluses (medically called calluses) are mistaken for corns. Calluses are also caused by friction, and are even more common. For example, if students use pens too much, calluses will form where their fingers touch the pen shaft; if people who work hold tools for a long time, calluses will also form where their palms hold them; people who walk too much will also have thick calluses on the front of their feet.

Callus Image source: Wikipedia

Plantar warts: Plantar warts can also be mistaken for corns. Plantar warts are skin growths caused by HPV infection. They tend to grow on the soles of the feet and are similar to corns, with a pimple-like appearance, but they usually have small black spots on the surface. They vary in size and number, are contagious, and are generally painless.

Plantar warts Image source: Wikipedia

Subungual exostosis: There is another rare disease called subungual exostosis. This is more related to trauma and is a reactive and reparative lesion under or beside the end of the toe bone. The most common site is the distal end of the big toe.

Subungual exostosis Image source: Chinese Medical Association Dermatology and Venereology Branch

How to treat and prevent corns?

To treat corns, we have to grasp the key points. The idea is to reduce pressure or redistribute pressure, remove the central keratin core to relieve recurrent pain, and finally reshape the skin and continue to prevent excessive friction. Therefore, in treatment, we must pay attention to routine care, take medical measures to treat existing corns, and strengthen prevention to avoid recurrence and rebound. In terms of care, it is recommended to wear suitable shoes, especially avoid too tight and hard shoes, wear less or no high heels and other heeled shoes. You can choose to use shock-absorbing insoles. If you stand or walk for a long time, pay attention to rest to reduce the burden on your feet. Regularly care for the skin of your feet, keep your feet clean, and deal with hard and dead skin in time.

Copyright images in the gallery. Reprinting and using them may lead to copyright disputes.

In terms of medical intervention, the treatment of corns is usually divided into conservative treatment and surgical treatment:

Conservative treatment: You can use ointments containing high concentrations of salicylic acid to help soften and dissolve the stratum corneum. It is best to use it under the guidance of a doctor to reduce side effects; friction-reducing pads can also relieve symptoms (search keywords "corn pads" and "corn anti-friction patches").

· Surgical treatment: For stubborn corns, it is even more important to see a doctor, who can remove the stratum corneum and the hard core in the center through surgery. Recovery is usually quick after surgery. However, if the inducing factors are not eliminated, corns may recur.

The key to preventing corns is to reduce pressure and friction on the feet. This can be achieved by choosing the right shoes, using insoles, trimming toenails regularly, and avoiding standing or walking for long periods of time. The idea is actually the same as the "care" section above. In addition, if there is a foot deformity, it is necessary to see a doctor in time and wear corrective devices according to the doctor's advice.

Summarize

As can be seen from the above, corns are thickened skin caused by long-term friction or pressure on the soles or toes. Although not serious, they can cause obvious pain and discomfort. For patients who already have corns, timely treatment can relieve symptoms and avoid recurrence and rebound. To prevent corns, you should pay attention to wearing suitable shoes, reducing foot pressure, and regularly taking care of the foot skin. However, before prevention and treatment, be careful not to misdiagnose other diseases as corns, such as calluses and plantar warts mentioned above. If necessary, do not hesitate to seek medical treatment in time.

References

[1]AlAboudAM,YarrarapuSNS.Corns.TreasureIsland(FL):StatPearlsPublishing;2024.

[2]Corns(Clavus).https://emedicine.medscape.com/article/1089807-overview

[3]WhatIsaFootCorn?https://www.verywellhealth.com/foot-corn-7111654

[4] UpToDate. Overview of benign lesions of the skin. https://www.uptodate.com/contents/zh-Hans/overview-of-benign-lesions-of-the-skin

Planning and production

Author: Tang Jiaoqing, MD, attending physician of dermatology

Review | Feng Jun, deputy chief physician of the Dermatology Department of Sinopharm Tongmei General Hospital