From the Guidelines
Verruca, also known as warts, are caused by the human papillomavirus (HPV), a DNA virus that infects the skin's epithelial cells. The etiology of verruca is attributed to the infection of keratinocytes by HPV, leading to epidermal thickening and hyperkeratinization 1. There are over 150 genotypically different types of HPV, with specific strains causing different types of warts. For example, HPV types 1,2,4,27, or 57 commonly cause common warts, while types 3 or 10 typically cause flat warts 1.
The virus enters the skin through tiny breaks or areas of trauma and infects the basal layer of the epidermis, causing excessive cell growth and the characteristic rough, raised appearance of warts. Transmission occurs through direct skin-to-skin contact or indirect contact with contaminated surfaces or objects. Some key points to consider about the etiology of verruca include:
- The virus can spread from one individual to another by direct contact or via the environment 1
- Warts are a common skin disease worldwide, with infection common in childhood, but can occur at any age 1
- Spontaneous clearance of the infection can occur at any time from a few months to years later, with half of warts in children clearing after 1 year and about two-thirds by 2 years 1
The most recent and highest quality study suggests that HPV is the primary cause of verruca, and understanding the different types of HPV and their role in causing various types of warts is crucial for effective management 1. Individuals with compromised immune systems are more susceptible to developing warts and may experience more extensive or persistent infections. The incubation period between infection and the appearance of warts typically ranges from 1 to 6 months, and many warts will resolve spontaneously within 1-2 years as the immune system recognizes and clears the viral infection.
From the Research
Verruca Etiology
- Verruca, also known as warts, are benign intraepidermal proliferations caused by human papillomavirus (HPV) infection 2, 3, 4, 5.
- The virus infects the epidermis, leading to an abnormal growth of skin cells, resulting in the formation of a wart 2, 3, 4.
- Verruca can occur on various parts of the body, including the skin and mucous membranes, such as the buccal mucosa 5.
- The exact mechanism of HPV infection and the development of verruca is not fully understood, but it is thought to involve the infection of skin cells and the subsequent proliferation of infected cells 4.
Risk Factors and Transmission
- Verruca can be transmitted through direct contact with an infected person or by coming into contact with a contaminated surface 4.
- The risk of developing verruca is higher in individuals with weakened immune systems, such as children and adults with certain medical conditions 2, 3.
- Verruca can also be spread through autoinoculation, where an individual touches a wart and then touches another part of their body, spreading the infection 4.
Clinical Presentation
- Verruca can present as a single lesion or multiple lesions, and can vary in size, shape, and color 2, 3, 6.
- The lesions are typically rough and scaly, and can be painful or tender to the touch 2, 6.
- In some cases, verruca can resolve on their own without treatment, but in other cases, treatment may be necessary to remove the lesion and prevent further spread of the infection 2, 3, 4, 6.