Is It a Callus or a Wart?

Both are considered non-cancerous skin lesions and the differences between warts and calluses are subtle.

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How Are Warts and Calluses Different?

Warts and calluses are both benign skin growths, but they differ in their appearance, location, and causes.

Wart

Verruca, more commonly known as a wart, is a benign skin growth that develops on different areas of the body and can take on many forms. They arise in response to a virus. Warts are contagious and very common. They can range from a mild annoyance to a chronic invasion. Warts can be spread through skin to skin contact or touching infected surfaces.[1] They are most commonly seen in children, young adults and those who have an immune system that does not work normally.[2]

Callus

Unlike warts, calluses are not contagious and do not result from an infection. Rather, they appear in response to increased pressure or repeated friction to an area. They most commonly appear on the hands and the bottom of feet and are seen in all ages.[3]

Corn

Just like calluses, corns also form on the skin in response to increased pressure of a particular area. They commonly appear on the top of feet, near the joint of the toe.[4] This is because the boney area on the toes does not have much cushion, and when constantly rubbed against a tight fitting shoe, it can create a thickened skin barrier for protection.

 

How Can You Tell a Wart vs Callus vs Corn?

Warts and calluses are often confused with each other. However, there are several features that define them from one another. Although not all warts are equal, there are some defining characteristics that distinguish them from calluses and other skin lesions. Some warts have many blood vessels, which present as tiny black dots on the surface. These dots are often confused as the “seeds of the wart”, but rather, they are capillaries.[1]

Calluses are generally hardened areas of skin but, unlike warts, they do not have blood vessels that are visible. The other defining characteristic is our natural skin lines. Since calluses are areas of thickened skin, the presence of skin lines throughout the hardened area will give a clue to a callus versus a wart, which will not have the normal skin lines present in the area of the wart.

It is common for ‘corn’ and ‘callus’ to be used interchangeably, which is reasonable since they both refer to the thickening and hardening of the skin. However, though the cause is similar, there are differences. Unlike calluses, corns contain a central core. This core can be hard or soft. The hardcore is the most commonly seen on the top of the foot.[4] Soft corns develop in between toes as a result of absorbing excess sweat in that area and are generally more painful than hardcore corns.[4]

Table 1. Characteristics of Warts vs Callus vs Corns

Wart

Callus

Corn

Skin lines are not visible

Multiple dark dots within the lesion

Clearly defined margins

Can occur anywhere on the foot

Skin lines go through the lesion

No blood supply in lesion

Diffuse margins

Present in weight-bearing areas

Can have defined or diffuse margins

Present on tops of feet, usually near the joint of the toes or in-between 

Hard or soft core

Can be painful

 

What Are the Typical Causes of Warts and Calluses?

Warts

Warts develop in response to an infection by the Human Papilloma Virus (HPV). This DNA virus invades the skin, causing epithelial cells to grow rapidly. There are over 120 strains of the HPV virus.[5] Different strains cause different types of warts in various locations.

Calluses

Unlike warts, calluses develop on the skin in response to increased pressure, repetitive friction, or other irritants.[3] When skin is exposed to continuous friction, the outermost layer of the skin, the stratum corneum, begins to thicken as a defensive mechanism. Some causes include factors such as foot deformities or poorly fitted shoes.

 

How Are Warts and Calluses Treated?

Warts

Many warts can spontaneously resolve within 2 years in young children but may take up to five years to resolve in adults.[1] It is not uncommon for the wart to come back and spread. Therefore, treatment is recommended, especially in adults.

There isn’t a specific antiviral therapy for warts, but there are many treatments available that work by destroying the infected skin. The most common treatments for wart removal are salicylic acid, cryotherapy, and surgical removal.

Callus

There are many treatments and management options for calluses, which can be managed at home as opposed to multiple trips to the doctor’s office. One of the common culprits of calluses are poorly fitted shoes.[3] Changing shoes could help to minimize callus formation. Other treatments aim at the removal of the thickened and hardened skin. A pumice stone can effectively smooth thickened areas after soaking in warm water.[6] Over the counter creams containing either urea or salicylic acid can be applied for the removal of calluses due to their exfoliating properties.[7,8] However, the first line of medical intervention is scalpel debridement.[9] This is a minor painless procedure that entails a licensed professional to remove thickened areas of skin with the edge of a scalpel or sharp blade.

Table 2 – Common Wart and Callus Treatments

Lesion

Agent

Administration

Advantage

Disadvantage

Wart

Patient-applied Salicylic Acid

Daily application by patient

Available over the counter. Not painful.

Requires up to many weeks to resolve. Patient’s consistent use is critical.

Provider-applied Salicylic Acid

Application by practitioner

Stronger formulation than over the counter. Not painful.

Frequent application by a provider.

Cryotherapy

Liquid nitrogen application by practitioner

Easy and potentially fewer treatments

Painful and scarring

Cantharadin

Application by practitioner

Not painful

Causes delayed blisters and may cause less itching

Candida antigen injection

Injection by practitioner

May stimulate the immune system to clear many warts including those that were not injected

Painful. Requires multiple treatments. May not work in those with weakened immune system

Surgical removal

Surgical removal of the wart by practitioner

Removal of wart (only small ones)

Painful and may scar, wart may recur

Laser therapy

Vascular laser by practitioner

May destroy blood vessels within wart

Painful and requires anesthesia. Requires multiple treatments

Callus

Shoe Change

Patient-driven shoe or insert modification

Could alleviate callus formation

Might not be the cause of the callus

Pumice Stone

Gentle removal of excess dead and thickened skin of the callus of area

At home treatment. Good maintenance regimen.

Not a permanent treatment. Must be done regularly.

Patient-applied Salicylic Acid or Urea Cream

Application to an area by patient

Available over the counter. Good maintenance regimen.

Not a permanent treatment. Must be done regularly.

Scalpel Debridement

Provider debris skin with scalpel

Quick and effective

Not permanent

 

When to Seek Help?

Consult a healthcare practitioner if:

  • If the lesion continues to enlarge in size
  • You want practitioner guided treatment
  • Your wart or callus does not improve despite over the counter treatments
  • You develop signs of an infection to the area, such as tenderness, pus, and drainage.

In some cases, lesions that seem like a wart may be a sign of something more serious such as a skin cancer and it is very important that new lesions are evaluated by a dermatologist. 

* This Website is for general skin beauty, wellness, and health information only. This Website is not to be used as a substitute for medical advice, diagnosis or treatment of any health condition or problem. The information provided on this Website should never be used to disregard, delay, or refuse treatment or advice from a physician or a qualified health provider.

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References

  1. Sterling JC, Gibbs S, Haque Hussain SS, et al. British Association of Dermatologists' guidelines for the management of cutaneous warts 2014. Br J Dermatol.2014;171(4):696-712; PMID: 25273231 Link to research.
  2. Bae JM, Kang H, Kim HO, et al. Differential diagnosis of plantar wart from corn, callus and healed wart with the aid of dermoscopy. Br J Dermatol.2009;160(1):220-222; PMID: 19067694 Link to research.
  3. Akdemir O, Bilkay U, Tiftikcioglu YO, et al. New alternative in treatment of callus. J Dermatol.2011;38(2):146-150; PMID: 21182541 Link to research.
  4. Freeman DB. Corns and calluses resulting from mechanical hyperkeratosis. Am Fam Physician.2002;65(11):2277-2280; PMID: 12074526 Link to research.
  5. Porro AM, Alchorne MM, Mota GR, et al. Detection and typing of human papillomavirus in cutaneous warts of patients infected with human immunodeficiency virus type 1. Br J Dermatol.2003;149(6):1192-1199; PMID: 14674896 Link to research.
  6. Baden HP. The pumice stone in dermatologic therapy. J Am Acad Dermatol.1980;2(1):29-30; PMID: 7354146 Link to research.
  7. HAGEMANN I, PROKSCH E. Topical Treatment by Urea Reduces Epidermal Hyperproliferation. Acta Derm Venereol (Stockh).1996;76:353-356
  8. Arif T. Salicylic acid as a peeling agent: a comprehensive review. Clin Cosmet Investig Dermatol.2015;8:455-461; PMID: 26347269 Link to research.
  9. Hashmi F, Nester CJ, Wright CR, et al. The evaluation of three treatments for plantar callus: a three-armed randomized, comparative trial using biophysical outcome measures. Trials.2016;17(1):251; PMID: 27189190 Link to research.