Difference Between Callus and Wart

Callus and wart are frequently seen dermatological problems. The lack of proper knowledge about these conditions has paved the way for the emergence of various myths and false beliefs about these diseases. Calluses are inflamed areas of thick skin. On the other hand, warts are abnormal skin growths caused by the Human Papilloma Virus (HPV). Calluses are due to the continuous rubbing of the skin against rough surfaces, but warts are due to the infection of the skin by HPV. This is the key difference between callus and wart.

CONTENTS

1. Overview and Key Difference
2. What is a Callus 
3. What is a Wart
4. Similarity Between Callus and Wart
5. Side by Side Comparison –  Callus vs Wart in Tabular Form
6. Summary

What is a Callus?

Calluses are inflamed areas of thick skin. These are formed by the continuous rubbing of skin against rough surfaces. Calluses are usually formed on the surfaces of the feet and hand that are prone to get friction injuries.

Causes

  • Tight footwear with a rough finish
  • Abnormalities in the gait
  • Wearing shoes without socks
  • Deformities of the feet

Figure 01: Callus

Treatment

  • Most calluses are self-limiting and disappear spontaneously.
  • If the calluses get infected, it is necessary to clean the site of infection and antibiotics should be given to prevent the systemic spread of the infection.
  • Occasionally salicylic acid is used to remove the calluses.

What is a Wart?

Warts are abnormal skin growths caused by the Human Papilloma Virus (HPV). Few recent discoveries have uncovered that there is an association between the HPV infection and cancer. The microscopic examination of the specimens from warts has revealed that the virus proliferates within the nucleus of the epidermal cells. There are over eighty types of HPV causing different forms of the wart.

HPV is the virus responsible for the cervical carcinomas. In immunosuppressed individuals, it can cause squamous cell carcinomas as well.

There are two categories of warts divided according to the anatomical region of the skin that they arise from,

  • Cutaneous Warts
  • Mucocutaneous warts

The chance of genital warts undergoing any malignant changes is very low, but HPV infection of the cervix caused by type 16 leads to dysplasia and subsequent malignant changes.

In patients taking immunosuppressive drugs, there is an extensive proliferation of warts, increasing the likelihood of squamous cell malignancies.

Epidermodysplasia verruciformis is a rare condition characterized by the widespread eruption of flat erythematous warty plaques that have the malignant potential.

Figure 02: Wart

Treatment

Warts usually occur in children and get resolved spontaneously within few months. They are treated with ointments and lotions containing salicylic acid, lactic acid or glutaraldehyde.

Liquid nitrogen is another frequently used chemical in treating warts. The use of liquid nitrogen is associated with minor adverse effects such as blistering and scarring. Heat cautery can also be used, but it causes more scarring and requires local anesthesia. Diathermy loop is the preferred method for the management of perianal warts. Podophyllin dissolved in benzene or alcohol is also used to remove warts, especially in the genital regions, but it is poisonous when ingested and can have serious hazardous outcomes if administered during pregnancy.

Other treatment modalities seldom used in the management of warts are,

  • Laser therapy
  • Immune enhancement
  • Bleomycin injections

What is the Similarity Between Callus and Wart?

  • Both are caused by the excessive thickening of the skin

What is the Difference Between Callus and Wart?

Callus vs Wart

Calluses are inflamed areas of thick skin. Warts are abnormal skin growths caused by the Human Papilloma Virus (HPV).
Causes
Calluses are caused by the continuous rubbing of skin against rough surfaces. Different strains of HPV cause warts.
Treatment
  • Most calluses are self-limiting and disappear spontaneously.
  • If the calluses get infected, it is necessary to clean the site of infection and antibiotics should be given to prevent the systemic spread of the infection.
  • Occasionally salicylic acid is used to remove the calluses.
Usually, warts get resolved spontaneously within few months. But if necessary they can be removed by using the following techniques,

  • Use of chemicals such as salicylic acid, glutaraldehyde, lactic acids and liquid nitrogen.
  • Laser therapy
  • Immune enhancement
  • Bleomycin injections

Summary – Callus vs Wart

Calluses are inflamed areas of thick skin whereas warts are abnormal skin growths caused by the Human Papilloma Virus (HPV). Although warts are caused by an infectious agent, calluses are mechanical injuries due to the continuous rubbing against rough surfaces. This is the major difference between callus and wart.

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References:

1. Buxton, Paul K. ABC of dermatology. London: BMJ, 2007.

Image Courtesy:

1. “30 muscle-ups, for time” by Drew Stephens (CC BY-SA 2.0) via Flickr
2. “Toe plantar wart 0147” By Dewdude (CC BY 2.5) via Commons Wikimedia