What causes warts and how do they work?

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From the Guidelines

Warts are caused by the human papillomavirus (HPV), which infects the skin and mucous membranes, leading to rapid skin cell growth and the formation of a wart. The development of warts involves the infection of keratinocytes, the predominant cell type in the epidermis, by HPV, resulting in epidermal thickening and hyperkeratinization 1. There are over 150 genotypically different types of HPV, with different strains causing different types of warts on various body parts. Warts work by the virus infecting the basal layer of the epidermis, where it incorporates its DNA into the host cell's DNA, causing the infected cells to produce viral proteins and multiply abnormally, creating the visible wart.

Some key points to consider:

  • Warts can spread through direct contact with infected skin or surfaces, and they're more likely to develop when the immune system is weakened.
  • Most warts are harmless and may disappear on their own as the immune system eventually recognizes and fights the infection, though this can take months or years.
  • People with compromised immune systems often have more persistent and widespread warts because their bodies struggle to combat the viral infection effectively.
  • The majority of common warts are caused by HPV types 1,2,4,27 or 57, and plane warts by HPV types 3 or 10 1.
  • Treatment options for warts include salicylic acid, which is thought to work by promoting exfoliation of epidermal cells and stimulating host immunity 1.

The most effective treatment for warts is salicylic acid, which is 16 times more likely to clear warts than placebo 1. It's essential to note that while there are various treatment options available, the choice of treatment depends on several factors, including wart size, location, and patient preference. Additionally, some treatments, such as podophyllin resin, have potential complications and should be used with caution 1.

In terms of prevention, correct and consistent male condom use can lower the chances of giving or getting genital warts, but such use is not fully protective 1. Furthermore, HPV vaccines are available and can protect against the types of HPV that cause most genital warts and cervical cancers 1.

Overall, warts are a common and generally harmless condition, but they can be persistent and troublesome for some individuals. Understanding the causes and treatment options for warts can help individuals make informed decisions about their care.

From the Research

Causes of Warts

  • Warts are caused by the human papillomavirus (HPV), of which there are over 100 types 2
  • HPV probably infects the skin via areas of minimal trauma, and risk factors include use of communal showers, occupational handling of meat, and immunosuppression 2
  • Warts can be transmitted by close skin-to-skin contact, and areas of skin that are broken or cut are more susceptible to being infected with the human papillomavirus virus 3

How Warts Work

  • Warts are a benign skin growth caused by the deoxyribonucleic acid virus named human papillomavirus, which infects the top layer of the skin and penetrates epithelial cells 3
  • Warts shed human papillomavirus, which can then infect other sites in the region or spread to other people 3
  • Most adults have developed immunity to the virus that causes warts, but children are more susceptible to warts because their bodies are less likely to have built immunity to the virus 3

Treatment of Warts

  • Treatment is aimed at relieving the patient's physical and psychological discomfort and at preventing the spread of infection by autoinoculation 4
  • Among the available medical and destructive therapeutic options for cutaneous warts, none is uniformly effective or virucidal 4
  • Cryotherapy and salicylic acid used in combination have been shown to have significantly higher remission rates 4
  • Other treatment options include intralesional bleomycin, intralesional candida antigen, contact immunotherapy, duct tape occlusion, photodynamic treatment, pulsed dye laser, and surgical procedures 2

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Warts (non-genital).

BMJ clinical evidence, 2014

Research

Warts: Pathophysiology, Types, Treatments, and Pharmaceutical Compounds.

International journal of pharmaceutical compounding, 2023

Research

Treatment of cutaneous warts: an evidence-based review.

American journal of clinical dermatology, 2012

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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