What causes Molluscum contagiosum (a viral skin infection)?

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From the Guidelines

Molluscum contagiosum is caused by the molluscum contagiosum virus (MCV), a DNA poxvirus that infects only humans. The virus is transmitted through direct skin-to-skin contact with an infected person or by touching contaminated objects such as towels, clothing, or toys. It can also spread through sexual contact in adults. The virus enters the skin through small breaks or hair follicles and replicates in the epidermis, causing characteristic dome-shaped, pearly or flesh-colored bumps with a central dimple. These lesions contain a white, cheese-like core filled with viral particles. The infection is particularly common in children, sexually active adults, and individuals with weakened immune systems. Key characteristics of the virus and its transmission include:

  • Direct skin-to-skin contact as a primary mode of transmission
  • Contaminated objects as a potential source of infection
  • Sexual contact as a mode of transmission in adults
  • Autoinoculation through scratching or shaving as a means of spreading the virus to different parts of the body While molluscum contagiosum often resolves without treatment within 6-12 months, as noted in a study published in Pediatrics 1, various treatment options exist, although none have proven highly successful. The study published in Pediatrics 1 discusses the management of molluscum contagiosum outbreaks, highlighting the use of treatments such as 10% potassium hydroxide and cryotherapy with liquid nitrogen for lesions in cosmetically bothersome locations or for patients with underlying skin conditions. However, the primary concern in managing molluscum contagiosum is preventing its spread and addressing the underlying cause of the infection, which is the molluscum contagiosum virus itself.

From the Research

Causes of Molluscum Contagiosum

  • Molluscum contagiosum is a self-limited infectious dermatosis caused by the molluscum contagiosum virus (MCV), a member of the Poxviridae family 2, 3, 4.
  • MCV is transmitted mainly by direct contact with infected skin, which can be sexual, non-sexual, or autoinoculation 2.
  • The virus infects keratinocytes and, after an incubation period of 2 weeks to 6 weeks, causes a breakdown of the skin barrier with the development of papules of variable size depending on the proper functioning of the immune response 4.
  • Individuals who can be infected with MCV include children, immunocompromised individuals such as organ transplant recipients, and Human Immunodeficiency Virus (HIV)-infected individuals 2, 4, 5.

Transmission and Risk Factors

  • The virus can be transmitted through direct contact with an infected person, contaminated objects, or autoinoculation 2, 3.
  • Risk factors for molluscum contagiosum include immunosuppression, skin barrier disruption, and close contact with an infected person 2, 4.
  • The infection is more common in children, sexually active adults, and immunocompromised individuals 2, 3, 4.

Virus Characteristics

  • MCV belongs to the genus Molluscipoxvirus and has a tropism for skin tissue 4.
  • The virus encodes for several inhibitory proteins responsible for circumventing the immune response through different signaling pathways 4.
  • MCV only infects humans and does not cause viremia 4.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Molluscum Contagiosum Virus: Biology and Immune Response.

Advances in experimental medicine and biology, 2024

Research

Imiquimod therapy for molluscum contagiosum.

Journal of cutaneous medicine and surgery, 2000

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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