Molluscum Contagiosum

Introduction

Molluscum contagiosum is a benign viral infection of the skin caused by the Molluscum contagiosum virus (MCV), a member of the Poxviridae family. It is characterized by skin-coloured, dome-shaped papules with central umbilication and is commonly seen in children and immunocompromised individuals.

The disease is self-limiting in immunocompetent individuals and usually resolves spontaneously within 12–18 months, although lesions may persist longer in some patients. Treatment may be indicated to reduce transmission, improve cosmetic appearance, relieve symptoms, or in patients with extensive or persistent disease.

Predisposing factors include:

• Young age (especially children)

• Close skin-to-skin contact

• Atopic dermatitis

• Sharing towels, clothing, or sports equipment

• Swimming pools and contact sports

• Immunocompromised states (e.g., HIV infection, immunosuppressive therapy)

Pathophysiology:The Molluscum contagiosum virus infects epidermal keratinocytes, producing localized epidermal hyperplasia and characteristic intracytoplasmic inclusion bodies (Henderson–Patterson bodies). Infection remains confined to the epidermis without systemic dissemination in most immunocompetent individuals.

Signs & Symptoms

• Skin-coloured, pearly, dome-shaped papules

• Characteristic central umbilication

• Smooth, firm lesions measuring approximately 2–5 mm

• Single or multiple lesions

• Mild itching may occur

• Surrounding eczema (molluscum dermatitis) may develop

• Lesions are usually painless unless secondarily infected

Common sites:

• Face (children)

• Neck

• Trunk

• Axillae

• Upper and lower limbs

• Genital region in sexually active adults

Course:

• Usually clears spontaneously within 12–18 months

• New lesions may appear through autoinoculation

• More persistent and extensive disease may occur in immunocompromised patients

Diagnostic Criteria

• Typical skin-coloured umbilicated papules

• Characteristic clinical appearance on physical examination

• History consistent with gradual spread by direct contact

• Diagnosis is primarily clinical

Investigation

Routine laboratory investigations are not usually required.

Investigations may be considered in atypical cases:

• Dermoscopy

• Skin biopsy if diagnosis is uncertain

• HIV testing in adults with extensive, recurrent, or unusually persistent lesions where clinically indicated

Consider differential diagnosis:

• Viral warts (verruca vulgaris)

• Varicella

• Milia

• Syringoma

• Basal cell carcinoma (solitary facial lesions in adults)

• Cryptococcosis (immunocompromised patients)

Treatment

Non-Pharmacological Treatment

• Reassure patients that the condition is usually self-limiting.

• Avoid scratching or squeezing lesions to reduce autoinoculation.

• Maintain good personal hygiene.

• Avoid sharing towels, clothing, or personal items.

• Cover lesions during contact sports or swimming where practical.

• Treat associated eczema if present.

Pharmacological Treatment

• Benzoyl peroxide: apply once daily for 4 weeks.

OR

• Tretinoin cream (topical) 2.5%: apply once daily for 4 weeks.

Surgical Treatment

• Cryotherapy.

OR

• Curettage.

Prevention

• Avoid direct skin-to-skin contact with active lesions.

• Do not share towels, clothing, razors, or personal items.

• Encourage regular hand hygiene.

• Cover visible lesions when participating in close-contact activities.

• Minimize scratching to reduce spread to other body sites.

Follow-up

• Review patients with persistent, extensive, or recurrent lesions.

• Monitor treatment response and adverse effects of topical therapy.

• Consider surgical treatment for persistent, symptomatic, or cosmetically significant lesions.

• Evaluate immunocompromised patients for underlying conditions if lesions are widespread, unusually large, or resistant to treatment.

Complications

• Secondary bacterial infection

• Autoinoculation leading to new lesions

• Molluscum dermatitis

• Cosmetic concerns

• Persistent or extensive disease in immunocompromised patients

Prognosis

The prognosis is excellent in immunocompetent individuals. Most lesions resolve spontaneously within 12–18 months without scarring, although temporary pigmentary changes may occur. Patients with immunosuppression may develop more numerous, larger, and persistent lesions requiring prolonged treatment.