Is Molluscum Contagiosum a Viral Infection?
Yes, molluscum contagiosum is definitively a viral skin infection caused by the molluscum contagiosum virus (MCV), a member of the Poxviridae family. 1
Etiology and Pathophysiology
Molluscum contagiosum is caused by a double-stranded DNA poxvirus that infects keratinocytes in the epidermis 2, 3. The virus is transmitted through:
- Direct skin-to-skin contact with infected individuals
- Self-inoculation (spreading from one body area to another)
- Contaminated fomites (towels, sports equipment, swimming pool surfaces)
- Sexual contact in adults 1, 3
Clinical Presentation
The infection manifests as skin-colored papules that develop a characteristic central umbilication as they mature 1. Key clinical features include:
- Appearance: Firm, rounded, pink or flesh-colored papules with shiny, dome-shaped surface and central depression
- Distribution: Most commonly affects trunk, face, and extremities in children 1
- Size: Typically small, but can present as giant lesions mimicking cysts or abscesses 4
- Symptoms: Usually asymptomatic, though may present with pain, itching, redness, or bacterial superinfection 1
Affected Populations
The infection predominantly affects three groups 1, 3, 5:
- Children aged 0-16 years (5-11% prevalence)
- Sexually active young adults
- Immunocompromised individuals (who may develop multiple, large, or atypical lesions)
Diagnostic Confirmation
While diagnosis is primarily clinical based on the characteristic umbilicated papules, histopathological examination reveals Henderson-Patterson bodies (viral inclusion bodies within enlarged keratinocytes), which are pathognomonic for this viral infection 4, 3.
Natural History and Prognosis
Uncomplicated molluscum contagiosum typically resolves spontaneously in 6-12 months, though complete resolution can take up to 4 years 1. This self-limited nature reflects the body's eventual immune response to the viral infection, though the lesions remain contagious until complete resolution.
Clinical Pitfall
In immunocompromised patients, large and multiple molluscum lesions with minimal conjunctival inflammation should prompt evaluation for underlying immunodeficiency (such as HIV), as this presentation is atypical for immunocompetent hosts 6, 7.