Rosen & Barkin's 5-Minute Emergency Medicine Consult (455 page)

• Molluscum contagiosum (MC) is a generally benign human disease characterized by multiple small, painless, pearly lesions.
  
• MC appears on epithelial surface and spreads through close contact or autoinoculation.
  
• Confined to the skin and mucous membranes
  
• 5–20% of patients with HIV have coinfection with MC.
  
• Found worldwide with an incidence of 2–8%, with higher distribution in tropical areas
  

• MC is caused by a double-stranded DNA poxvirus of the
  Molluscipox
  genus
  
• Transmission in children is by direct skin-to-skin contact, fomites, or pool or bath water.
  
• Transmission in adults is most often by sexual contact; autoinoculation is common at any age.
  
• There are rare reports of transmission to infants during childbirth.
  

DIAGNOSIS

• Incubation period: 14–50 days
  
• Patients are usually asymptomatic, with occasional pruritus or tenderness.
  
• 10–25% of patients may have eczematous reaction surrounding the lesions.
  
• Untreated lesions in immunocompetent hosts usually resolve within several months but can last up to 5 yr.
  

• Lesions are smooth-surfaced, firm, spherical papules 2–6 mm in diameter.
  
• May be flesh colored, white, translucent, or light yellow
  
• Lesions have a waxy, curd-like core composed of collagen–lipid-rich material containing large numbers of maturing virions
  
• Distinctive central umbilication in 25%
  
• Atypical presentations include nonumbilicated, persistent, disseminated, or giant lesions, usually in the setting of immunosuppression.
  
• Distribution:
  
  • Children:
    
    • Face
      
    • Trunk
      
    • Extremities
      
  • Healthy adults:
    
    • Genitals
      
    • Lower abdomen
      
    • Occasionally perioral
      
  • Rarely on palms and soles
    
• MC is commonly seen with HIV infection, causing atypical involvement of face, neck, and trunk, lesions to 1.5 cm, and a progressive course. Lesions may also appear with initiation of highly active antiretroviral therapy (HAART) as a manifestation of the immune reconstitution inflammatory syndrome.
  
• Occasional intraocular or periocular involvement presenting as trachoma or chronic follicular conjunctivitis
  

• History and careful skin exam
  
• Skin biopsy for confirmation
  
• Lesions in adult men necessitate evaluation for an immunocompromised state.
  
• MC in children is rarely associated with immunodeficiency, and usually no further evaluation is needed.
  

• Test for immunocompromised state if no clear etiology:
  
  • CBC with differential
    
  • HIV if indicated
    
• If anogenital lesions:
  
  • Consider syphilis, hepatitis C, HIV
    

Skin biopsy for confirmation

• Basal cell carcinoma
  
• Histiocytoma
  
• Keratoacanthoma
  
• Intradermal nevus
  
• Darier disease
  
• Nevoxanthoendothelioma
  
• Syringoma
  
• Epithelial nevi
  
• Sebaceous adenoma
  
• Atopic dermatitis
  
• Dermatitis herpetiformis
  
• Mycosis fungoides
  
• Jessner lymphocytic infiltration
  
• Cryptococcus neoformans
  

TREATMENT

Maintain universal precautions.

Not applicable in routine cases.

• Aimed at destruction or removal of virus-infected epithelial cells and is indicated to prevent autoinoculation and transmission:
  
  • Intervention is not always indicated: Lesions are self-limited in immunocompetent hosts.
    
  • Untreated immunocompromised patients are at greater risk for secondary inflammation and bacterial infections
    
• If treatment is necessary, consider referral to dermatology.
  
• If dermatology referral is not an option, physical treatment modalities generally most effective:
  
  • Curettage after local anesthesia with EMLA (eutectic mixture, lidocaine, prilocaine) or ethyl chloride
    
  • Cryotherapy with liquid nitrogen
    
  • Podophyllin, trichloroacetic acid, cantharidin, tretinoin, and cidofovir applied topically are variably effective.
    
  • Repeatedly applying adhesive tape to the lesions as a means of removing the superficial epidermis
    
• Griseofulvin and methisazone orally for extensive disease have given mixed results.
  
• HAART has been effective in reducing incidence in HIV-infected patients.
  
• Topical imiquimod has shown effectiveness in several small studies.
  
• Examine sexual partners for MC and other sexually transmitted diseases:
  
  • Patients should avoid contact sports, swimming pools, shared baths and towels, scratching, and shaving until lesions have resolved.
    
• Re-examine treated patients for recurrence every 2–4 wk; 2–4 treatments are often needed to clear lesions completely.
  
• Discourage picking and scratching lesions, a common habit, as it may lead to scarring or pigment alteration.
  

• Cantharidin 0.9% solution with equal parts of acetone and flexible collodion: Apply topically 1–3 treatments every 7 days or until resolution.
  
• Imiquimod 5%: Apply topically daily for 3–5 consecutive days for 16 wk.
  
• Podophyllin (podofilox 0.5%): Apply topically q12h for 3 days, withhold for 4 days; repeat 1-wk cycle up to 4 times until resolved.
  
• Tretinoin 0.1%: Apply topically q12h for 10 days or until resolution of lesions.
  
• Trichloroacetic acid (50–80%): Apply and cover with bandage 5–6 days.
  
• Oral cimetidine (40 mg/kg/d) in 2 div. doses for 2 mo has been used to treat extensive infections; however, further study is needed to determine efficacy.
  

FOLLOW-UP

Widespread disease with extensive superinfection in an immunocompromised host

Patients without extensive superinfection may be safely treated as outpatients.

Consider referral to dermatology if treatment or confirmatory testing is necessary.

Re-examine treated patient for recurrence every 2–4 wk.

• Active nonintervention is an option in immunocompetent hosts.
  
• Search for an immunocompromised state if no clear etiology.
  
• Physical destruction of lesions is often most effective treatment vs. medication.
  

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  . 2001;12(2):vi, 229–242.
  
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  2004;73(3):202–206.
  
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  Am Fam Physician
  . 2009;80:864–865.
  
• Hanson D, Diven DG. Molluscum Contagiosum (review).
  Dermatol Online J.
  2003;9(2):2.
  
• Sladden MJ, Johnston GA. Common skin infections in children.
  Br Med J
  . 2004;329:403.
  
• Sornum A. A mistaken diagnosis of molluscum contagiosum in an HIV-positive patient in rural South Africa.
  BMJ Case Rep.
  2012;2012. doi:10.1136/bcr-2012-007539.
  
• van der Wouden JC, van der Sande R, van Suijlekom-Smit LW, et al. Interventions for cutaneous molluscum contagiosum (review).
  Cochrane Database Syst Rev
  . 2009;CD004767.
  

CODES

078.0 Molluscum contagiosum

BASICS