What Are Corns and Calluses and Why Do We Get Them?

23 November, 2020
Calluses are an aesthetic problem that affects self-esteem and body image. That's why it's important that we know why we get them and how to prevent them. Those more prone to them are diabetics and athletes.

Corns and calluses are types of localized hardening, found mainly on the soles of the feet. They’re also known as helomas.

It’s a condition that often affects athletes or patients that are exposed to irregular shoe friction or walking problems. Also included are older adults, diabetics, and amputees.

What are corns and calluses?

Corns and calluses are thick, uncomfortable, and common skin lesions. They’re a result of repeated mechanical trauma thanks to friction or pressure forces happening on the skin.

People with darker skin are more likely to develop them. They’re also more likely to develop on the feet, at the back of the toes, in between the toes, and on the soles.

What are the signs and symptoms?

This form of hyperkeratosis usually presents itself as a dry, hard, rough, flesh-colored papule with a whiteish center. The center is the nucleus. Therefore, they usually grow on bony prominences.

They’re painful, making it difficult to walk and stand up, but asymptomatic to touch. What’s more, as keratin growth and thickening increases, corns and calluses can cause severe pain.

It’s often difficult to differentiate between corns and plantar warts. However, if a doctor puts perpendicular pressure on the callus with their finger, they’ll touch the bone and the patient will feel pain. Doing this to warts isn’t usually painful.

A person wearing high heels.
Wearing inappropriate footwear is likely to cause corns to appear.

Why do corns and calluses grow?

Inappropriate footwear, unusual use of the feet, and high levels of activity product pressure and friction that leads to corns and calluses. This is why athletes are more likely to suffer from them.

Therefore, repeated friction and pressure of the skin covering bony areas create a thickening that results in corns or calluses. This extra thickness is a protective reaction that the body creates. It produces excess skin to prevent blisters.

This explains why they’re more likely to form near the metatarsal and phalangeal condyles, and their appearance on patients with foot deformities. The lower extremities are the most affected by the pressure they bear.

Also read: How to get rid of germs and dead skin on your feet

Types of corns and calluses

There are two main types of this condition. However, there’s usually a third that manifests as multiple non-painful caps within the plantar corns, on parts of the sole that don’t support pressure.

Hard corn

A hard corn is the most common type of callus. It forms most often on the lateral and dorsal side of the fifth toe, as well as on the dorsal side of the interphalangeal joints of the smaller toes.

Soft corn

A soft corn is a painful hyperkeratotic lesion that usually forms in between the toes, especially the fourth. This location often leads to maceration and sometimes to the appearance of a bacterial or fungal infection.

How to treat calluses

Lesions tend to disappear once the pressure causing them stops. Treatment usually aims to reduce pain and discomfort. Despite this, calluses usually recur.

Topical treatments for corns or calluses

Patients can apply topical keratolytic medications, including salicylic acid, to corns. Urea dressings at 20% and 50%, silver nitrate, and hydrocolloids are also used in this indication.

These techniques are more effective for some lesions. In turn, topical keratolytic agents can also help to remove lesions by softening the corns. Physically removing corns has been shown to improve quality of life and pain.

Ablative laser

Lasers can be used to treat corns, instead of exfoliating them with a scalpel. However, in some patients, lesions typically recur, especially if there’s continued pressure and friction.

Conservative treatment

Any mechanical problems and deformities should be treated with appropriate conservative treatment. Meaning, wearing suitable footwear and soft cushions that reduce friction and improve comfort.

Surgically

A surgical approach tries to remove the underlying cause of the corns, such as bony prominences. It’s usually recommended after other more conservative treatment methods have failed, according to American Family Physician publications.

Home tips for eliminating corns

Try soaking the corns in warm water for 20 minutes. After this, gently rub the callus with your finger or a pumice stone.

A callus on a foot.
Treatments range from a conservative approach to ablative surgery.

How to prevent corns and calluses from appearing

Management, in fact, begins with prevention. Therefore, poorly fitting shoes and mechanical trauma to the affected area should be avoided. This applies especially to intensively trained athletes.

Calluses aren’t contagious, and viruses don’t cause them. It should also be pointed out that cutting toenails will avoid any pressure or repeated trauma that could lead to injures developing.

Risks of corns and calluses

While corns and calluses are a chronic and recurring problem, most of them will gradually disappear once repeated pressure or friction stops. However, if they don’t disappear, or begin to cause severe pain, the patient must visit a dermatologist or podiatrist.

In people with diabetes or another condition that causes poor blood flow to the feet, there’s an increased risk of complications. These patients need strict control with an examination of their extremities to detect the problem that can lead to blisters early.

  • Freeman DB. Corns and calluses resulting from mechanical hyperkeratosis. Am Fam Physician. 2002 Jun 1;65(11):2277-80. PMID: 12074526.
  • Kovar P. Vorsicht bei der Selbstbehandlung von Schwielen und Clavi! [Calluses, corns and others – beware of the self-treatment!]. MMW Fortschr Med. 2016 Dec;158(21-22):64-66. German. doi: 10.1007/s15006-016-9106-z. PMID: 27966126.
  • Singh D, Bentley G, Trevino SG. Callosities, corns, and calluses. BMJ. 1996 Jun 1;312(7043):1403-6. doi: 10.1136/bmj.312.7043.1403a. PMID: 8646101; PMCID: PMC2351151.
  • Güngör S, Bahçetepe N, Topal I. Removal of corns by punch incision: a retrospective analysis of 15 patients. Indian J Dermatol Venereol Leprol. 2014 Jan-Feb;80(1):41-3. doi: 10.4103/0378-6323.125491. PMID: 24448122.
  • Haneke E. Differentialdiagnose und Therapie von Schwielen, Hühneraugen und Plantarwarzen [Differential diagnosis and therapy of calluses, corns and plantar warts (author’s transl)]. Z Hautkr. 1982 Feb 15;57(4):263-72. German. PMID: 6210994.
  • Balanowski KR, Flynn LM. Effect of painful keratoses debridement on foot pain, balance and function in older adults. Gait Posture. 2005 Dec;22(4):302-7. doi: 10.1016/j.gaitpost.2004.10.006. Epub 2005 Jan 7. PMID: 16274911.
  • Soto, Manuel Romero, et al. “Estudio de prevalencia de patologías podológicas y grado de dependencia en personas mayores de 65 años.” El peu 30.3 (2010): 104-111.
  • Chicharro, Esther, et al. “Heloma duro vs tiloma.” El Peu 27.4 (2007): 229-235.
  • Ibáñez, MA Campillo, A. Prós Simón, and J. Blanch Rubiò. “Tratamiento de callos y clavos.” FMC-Formación Médica Continuada en Atención Primaria 10.5 (2003): 349-358.
  • Couselo-Fernández, I. G. N. A. C. I. O., and Jose María Rumbo-Prieto. “Riesgo de pie diabético y déficit de autocuidados en pacientes con Diabetes Mellitus Tipo 2.” Enfermería universitaria 15.1 (2018): 17-29.
  • García, Elisabeth Thió. “Resultados en el tratamiento láser de onicomicosis y helomas por inclusión.” El Peu 37.2 (2016): 26-34.