Molluscum Contagiosum

Content of This Page

 1- Introduction

2- Causes

3- Symptoms

4- Investigations & Lab Results

5- Complications

6- Treatment

Introduction

Molluscum contagiosum is a common, contagious viral skin infection caused by the molluscum contagiosum virus (MCV), which belongs to the poxvirus family. It primarily affects children but can also occur in adults, especially those with weakened immune systems or through sexual contact.

The infection is characterized by the appearance of small, firm, dome-shaped, flesh-colored papules with a central dimple or umbilication. These lesions typically appear on the face, trunk, limbs, and genital areas.

Molluscum contagiosum is usually a benign, self-limiting condition that resolves spontaneously within months to a few years but can spread easily through direct skin-to-skin contact, autoinoculation (self-spreading), or contaminated objects like towels

© image from www.researchgate.net

Causes

  • Direct skin-to-skin contact: The most common way, especially in children during play or close contact.

  • Autoinoculation: The virus can spread from one area of the body to another by scratching or touching lesions.

  • Fomite transmission: Contact with contaminated objects like towels, clothing, or toys.

  • Sexual contact: In adults, especially when lesions occur in the genital area, molluscum contagiosum can be sexually transmitted.

Henderson Patterson bodies © image from www.researchgate.net

Symptoms

  • Appearance of small, firm, dome-shaped papules or nodules on the skin

  • Lesions are typically flesh-colored, pearly, or waxy with a central umbilication (a small dimple or pit in the center)

  • Size ranges from 2 to 5 millimeters but can be larger in some cases

  • Lesions are usually painless and not itchy, but mild itching or irritation can occur

  • Lesions often appear in clusters or groups and can spread over time due to scratching or autoinoculation

  • Commonly affected areas: face, trunk, arms, and legs in children; genital and lower abdominal areas in adults (especially sexually transmitted cases)

  • In immunocompromised patients, lesions can be larger, more numerous, and persist longer

Investigations & Lab Results

1. Clinical Examination

  • Visual inspection of typical umbilicated, pearly papules is usually sufficient.

2. Skin Scrapings or Curettage

  • Microscopic examination of material obtained from lesion scraping or curettage

  • Characteristic finding: Molluscum bodies (also called Henderson-Patterson bodies) — large eosinophilic cytoplasmic inclusion bodies within keratinocytes seen on light microscopy

  • These are diagnostic of molluscum contagiosum

3. Histopathology (Skin Biopsy)

  • Used if diagnosis is unclear

  • Shows hyperplastic epidermis with molluscum bodies in the cytoplasm of keratinocytes

  • Confirms viral infection and rules out other skin conditions

4. Polymerase Chain Reaction (PCR)

  • Highly sensitive for detecting viral DNA

  • Rarely needed in routine practice but useful in research or atypical cases

5. Differential Diagnosis

  • Other papular lesions such as warts, basal cell carcinoma, or folliculitis may be considered and ruled out clinically or histologically.

Complications

  • Secondary Bacterial Infection:

    • Due to scratching or disruption of the skin barrier, lesions may become infected with bacteria like Staphylococcus aureus, causing redness, pain, swelling, or pus.

  • Eczema or Inflammatory Reaction:

    • Some patients develop an eczematous or inflammatory rash around the lesions (called molluscum dermatitis), causing itching and redness.

  • Spread and Autoinoculation:

    • Lesions can multiply and spread to other parts of the body, especially with scratching or shaving.

  • Scarring:

    • Lesions that are repeatedly irritated, scratched, or treated aggressively may leave small scars.

  • Cosmetic Concerns:

    • Especially when lesions are numerous or in visible areas, causing psychological distress.

  • Widespread or Persistent Infection in Immunocompromised Individuals:

    • Lesions can be larger, more numerous, and last longer, requiring more aggressive treatment.

Treatment

1. Watchful Waiting

  • Many cases resolve without treatment over time

  • Avoid scratching to prevent autoinoculation and secondary infection

2. Physical Removal

  • Curettage: Scraping lesions with a curette — immediate removal but can cause mild discomfort

  • Cryotherapy: Freezing lesions with liquid nitrogen

  • Laser Therapy: For resistant or widespread lesions

3. Topical Treatments

  • Cantharidin: Causes blistering and peeling of lesions

  • Podophyllotoxin: Antimitotic agent, used especially for genital lesions

  • Imiquimod: Immune response modifier (variable effectiveness)

  • Topical retinoids: Promote skin turnover

4. Other Treatments

  • Oral cimetidine: Sometimes used in children with multiple lesions (limited evidence)

  • Antibacterial treatment: If secondary bacterial infection occurs

5. Patient Education and Hygiene

  • Avoid sharing towels, clothing, or other personal items

  • Keep skin clean and dry

  • Avoid scratching or picking lesions to prevent spread

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