Moluscum Contagiosum

Common, benign viral skin infection characterized by smooth, flesh-colored to pearly papules with central umbilication.

Aetiology

• Virus: Pox Virus — Molluscum Contagiosum Virus (MCV) – a DNA virus from the Poxviridae family
• MCV type 1 → most common, especially in children
• MCV type 2 → more common in adults, sexually transmitted

• Direct skin-to-skin contact

• Autoinoculation (scratching → spread)

• Fomites (towels, sports equipment)

• Sexual contact (genital lesions in adults)

• Atopic dermatitis patients

• Immunocompromised (HIV, long-term steroids)

Pathophysiology

• Virus infects epidermal keratinocytes.

• Causes localized epidermal hyperplasia.

• Produces characteristic intracytoplasmic inclusion bodies (Henderson–Patterson bodies).

Clinical Presentation

• Discrete, dome-shaped papules, 2–5 mm

• Smooth, shiny, skin-colored or pearly lesions

• Delle — Central umbilication (pathognomonic)

• Mild pruritus; usually painless

• Common sites:
• Children: face, trunk, extremities
• Adults: genital, abdomen, inner thighs (often sexually transmitted)

• In HIV or immunosuppression → numerous, larger, more persistent lesions

Investigations

• Dermoscopy: central pore/plug

• Histopathology: Henderson–Patterson inclusion bodies (diagnostic)

• PCR if atypical

Management

• Cosmetic concern

• Pruritic/inflamed lesions

• Genital involvement

• Immunosuppressed state

• Risk of spread (school, sports)

• Curettage/enucleation (effective, immediate result)

• Cryotherapy with liquid nitrogen

• Needle extraction/ expression (small lesions)

• Cantharidin (blistering agent) 0.7% and 0.9%, left on lesion for 3-4 hr

• Podophyllin cream 0.3% and 0.5% applied 2x/day for 3 days consecutively

• Imiquimod (immune modulator)

• Potassium hydroxide (KOH 5–10%)

• Salicylic acid for keratolysis

• Laser therapy (CO₂, pulsed dye) for resistant cases