1. Background

• caused by a large, double-stranded DNA poxvirus
• this poxvirus replicates in the cytoplasm of infected epithelial cells and thus Molluscum Contagiosum is considered an infection of the epidermis which should not result in scarring
• humans are the only host of this poxvirus
• the incubation period is usually 2-7 weeks but may be as long as 6 months (period of time from acquisition of the virus to appearance of the papules)
• unknown period of communicability
• this poxvirus has a low infectivity rate

2. Routes of Transmission

• the poxvirus is spread by direct contact:
  • with an infected person
  • through sexual contact
  • from fomites found on towels, washcloths, etc.
  • by autoinoculation from scratching

1. Skin Manifestations

• pearly, skin-coloured, dome-shaped, smooth papules with a central plug of cheesy-appearing material which can be expressed
• papules are usually 1-5 mm in size although some can be as large as 1-2 cm
• papules occur at any site on the skin but there is a predilection for the face, eyelids, neck, axilla, abdomen, arms, and thighs
• may also be found in clusters on the genitalia or in the groin and may not be associated with sexual activity
• erythema or a dermatitis (molluscum eczema) may surround some of the papules
• usually there are less than 20 papules present at one time
• the papules may be pruritic
• atopic and immunosuppressed patients may have more intense, widespread, and/or larger lesions

2. Complications

• conjunctivitis with papules on the eyelid margin
• lesions may involve the conjunctiva or cornea

1. Light Microscopy

• characteristic intracytoplasmic inclusions are seen within the cheesy material expressed from the central core with 10% KOH, Wright or Giemsa stains

2. Electron Microscopy

• will identify poxvirus within the material expressed from the central core

1. Supportive

• a self-limited infection which usually resolves after 6-9 months
• some papules can last for years and spread to other sites on the skin
• infected persons should avoid sharing baths, towels, washcloths, etc.
• more likely to treat atopic and immunosuppressed patients

2. Treatment Options

• any treatment which removes the central core from a papule results in resolution:
  • liquid nitrogen applied for 6-9 seconds
  • application of cantharidin (0.7%)
  • application of peeling agents such as salicylic and lactic acid preparations
  • direct extrusion of the core by needle, sharp curette, or comedo extractor
• consider cured if lesion-free for 4 or more months

1. Committee on Infectious Diseases. 1997 Red Book. 24th Edition. p. 364, (1997).

2. Rudolph, A.M., Rudolph's Pediatrics. 19th Edition. p. 931, (1991).