Molluscum Contagiosum
Molluscum contagiosum is a benign infection of the epidermis caused by the molluscum contagiosum virus (MCV), a large double-stranded DNA virus of the genus Molluscipoxvirus, family Poxviridae. It produces dome-shaped, smooth, shiny papules that are skin-colored or pale pink, with a distinctive central dimple (umbilication) containing a soft, cheesy core packed with virus particles. MCV spreads mainly through direct skin-to-skin contact, through contaminated personal items (towels, swimwear, sports equipment) or, in adults, through sexual contact.
Although MCV stays entirely within the epidermis and never enters the bloodstream, it is remarkably good at hiding from the immune system. The virus makes its own proteins that neutralize interleukin-18 (IL-18 binding protein), block chemokines and prevent programmed cell death (apoptosis) of keratinocytes. This lets it persist inside host cells for months without provoking a strong inflammatory response.
At Haute-Derma, our approach to molluscum contagiosum follows current medical standards and has three main goals: rapid confirmation with dermoscopy, complete removal of lesions using painless minimally invasive techniques, and preventing self-spread of the virus (autoinoculation) as well as dark marks or scarring after treatment.
Pathogenesis and MCV Genotypes
Genotypes and Epidemiology
- MCV-1: The most common type, responsible for 75–90% of all cases and the main cause of molluscum in children.
- MCV-2: Usually seen in adults, transmitted sexually or occurring in people with weakened immunity (HIV/AIDS).
- MCV-3 and MCV-4: Very rare in practice and found mainly in certain geographic regions.
Henderson-Paterson Bodies and Viral Replication
- The virus enters through small breaks in the epidermis and begins replicating in the cytoplasm of cells in the spinous layer (stratum spinosum).
- As infected cells mature and move upward, viral replication surges in the cytoplasm, forming large eosinophilic inclusions (up to 35 µm across) known as Henderson-Paterson bodies (molluscum bodies).
- The growing inclusions push the cell nucleus aside and break down the center of the epidermal lobule, creating an opaque white, cheese-like core that contains countless live virus particles.
Clinical Features
Pediatric Molluscum:
- Who: Most common in children aged 2–11, especially those with a history of atopic dermatitis.
- Where: Scattered over the face, neck, armpits, elbows, abdomen and groin folds. Never on the palms or soles.
- Other features: Often accompanied by molluscum dermatitis, in which the skin around the bumps becomes red, dry and itchy as the immune system reacts to viral antigens.
Sexually Transmitted Molluscum (STI / Adult Molluscum):
- Who: Sexually active adults.
- Where: Pubic area, base of the penis, vulva, inner thighs, buttocks and around the anus.
- Features: Usually 10–20 papules; screening for other sexually transmitted infections (genital warts, chlamydia, syphilis) is needed at the same time.
Giant and Treatment-Resistant Molluscum (Immunocompromised Patients):
- Who: People with HIV (CD4 < 100 cells/µL), organ transplant recipients or those on long-term immunosuppressive drugs.
- Features: Large lesions (>10 mm) that merge into warty, tumor-like plaques, with hundreds of bumps on the face and neck. They are easily mistaken for squamous cell carcinoma (SCC) or deep fungal infection (Cryptococcus, Histoplasma).
Differential Diagnosis of Papular and Wart-Like Skin Lesions
| Molluscum Contagiosum (MCV) | Flat Warts (HPV) | Genital Warts (HPV 6/11) |
|---|---|---|
| Dome-shaped papule with a central dimple | Flat-topped papule, rough surface, brown or skin-colored | Soft, cauliflower-like or shaggy growths |
| Sticky white core (molluscum body) | No core; black dots on the surface | No core |
| Opaque white center, crown vessels | Black dots (thrombosed capillaries) | Looped vessels, papillary projections |
| Usually painless, mildly itchy | Painless, not itchy | Painless, mildly itchy when moist |
Diagnosis at Haute-Derma
Clinical Examination and Dermoscopy: Dermoscopy shows an opaque white or yellowish-gray central area with a network-like pattern (corresponding to Henderson-Paterson bodies), surrounded by crown-pattern vessels or dotted vessels radiating toward the edge of the papule.
Crush Preparation of the Core (Tzanck Smear / Light Microscopy): The core is gently extracted, squashed between a slide and coverslip and examined under a light microscope, either unstained or with Giemsa stain. Numerous large, oval Henderson-Paterson bodies are seen compressing the cell nuclei.
Skin Biopsy (Atypical Cases): Reserved for giant lesions or lesions in immunocompromised patients. Histology shows a cup-shaped downgrowth of the epidermis, with enlarged keratinocytes whose cytoplasm is filled by eosinophilic inclusions.
Treatment and Cosmetic-Focused Management at Haute-Derma
Procedures With the Best Cosmetic Outcome (First Choice)
- Core extraction (micro-curettage):
- EMLA 5% numbing cream is applied for 30–45 minutes.
- The doctor uses fine microsurgical forceps or a curette to remove the white, virus-filled core completely.
- The area is disinfected immediately with octenidine dihydrochloride or nano-silver solution. This is the most effective method and clears each lesion in a single treatment.
- Liquid nitrogen cryotherapy: A liquid nitrogen spray freezes each papule for 5–10 seconds, creating a 1 mm ice halo around its base. Suitable for small, scattered lesions.
Chemical and Topical Treatments
- Targeted chemical application: Trichloroacetic acid (TCA 25–30%) or cantharidin 0.7% is dabbed precisely into the central dimple. Cantharidin raises a sterile blister in the epidermis that lifts the lesion out.
- Immune-activating creams:
- Imiquimod 5% cream: applied 3 times a week at bedtime, it stimulates TLR-7 to produce interferon-alpha locally, helping clear the virus.
- Topical retinoids (adapalene 0.1%, tretinoin 0.05%): applied every evening, they normalize keratinization of the epidermis and speed up clearance of the papules.
Micro CO2 Laser and Post-Procedure Recovery
- Superpulse CO2 laser: Used for giant molluscum, lesions on the eyelids or treatment-resistant lesions. The 10,600 nm wavelength precisely vaporizes infected tissue without bleeding or damage to the basement membrane.
- Aftercare at Haute-Derma: A moisturizer containing ceramides, zinc oxide, B5 and niacinamide is applied for 7 days to speed up epidermal repair and prevent post-inflammatory hyperpigmentation (dark marks).
