Molluscum contagiosum

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Molluscum contagiosum is due to a  poxvirus infection of the skin. It is a benign spontaneously resolving, painless infection lasting months and occasionally up to 2 years. It is common in young children, where lesions occur anywhere on the body (including the genitals), especially in skin folds. In adults it can be seen as a sexually acquired infection  affecting the genitals, pubic region, lower abdomen, upper thighs and/or buttocks.
In HIV infection and other immunosuppressive conditions, lesions may be widespread and atypical.
Those with atopic dermatitis may also have disseminated molluscum.

The opportunity to screen for other STIs should be taken as genital molluscum may be a marker of risk for sexually transmitted infections. This should include testing for HIV, especially where lesions are multiple and widespread, large, or seen on the face. Transmission is via direct skin to skin contact. Autoinnoculation is common especially with scratching, areas of dermatitis or friction.

DIAGNOSIS

Lesions are usually  multiple and occur in clusters,presenting  as  smooth-surfaced, firm, dome-shaped papules with central umbilication. They are found on keratinized skin, especially skin folds and hair bearing areas, and can affect almost any part of the body. Genital molluscum may be confused with ectopic sebaceous glands, and patients may confuse lesions with genital warts. 
Localised redness and soreness may be due to secondary bacterial infection. Redness also occurs prior to natural resolution. Approximately 10% of adults develop eczema around lesions that resolves as the lesions regress.

MANAGEMENT

Some treatments may shorten the disease course, but this should be balanced against possible side-effects. Molluscum infection resolves naturally, usually leaves no long-term sequelae, and it is therefore important that any therapy chosen is gentle and has minimal side-effects. 
Treatment is primarily for cosmetic reasons;  patients should be warned of risks of autoinoculation and advised against shaving or waxing their genital regions, to prevent further spread of lesions, secondary infection and scarring.

TREATMENT

Untreated, lesions can persist  for 6 months to 2 years. Most individual lesions clear by 3 months.
Treatments induce local epidermal inflammation and various treatments are effective. There is no clear evidence supporting one treatment over another. 

The usual mode of treatment is cryotherapy: 

  • Apply liquid nitrogen with cryospray until a halo of ice surrounds the lesion. 
  • Repeat treatments may be performed weekly until resolution

Alternative treatments:
Podophyllotoxin 0.5% cream or paint twice daily 3 days per for 4 weeks, or Imiquimod 5% applied sparingly 3 times per week for up to 16 weeks has shown some limited efficacy. 

Podophyllotoxin and imiquimod should be avoided in pregnancy and breastfeeding. 

Other destructive treatments such as piercing with a sterile 19 gauge needle with expression of the pearly core and application of tincture of iodine or phenol, or diathermy / curettage under local anaesthesia are seldom performed owing to issues of pain and potential scarring.

Disclaimer
The content of these treatment guidelines is for information purposes only. The treatment guidelines are generic in character and should be applied to individuals only as deemed appropriate by the treating practitioner on a case by case basis. Alfred Health, through MSHC, does not accept liability to any person for the information or advice (or the use of such information or advice) which is provided through these treatment guidelines. The information contained within these treatment guidelines is provided on the basis that all persons accessing the treatment guidelines undertake responsibility for assessing the relevance and accuracy of the content and its suitability for a particular patient. Responsible use of these guidelines requires that the prescriber is familiar with contraindications and precautions relevant to the various pharmaceutical agents recommended herein.

Last Updated December 2014