Published on 19/03/2015 by admin
Filed under Dermatology
Last modified 19/03/2015
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Aysha Javed and Ian Coulson
Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports
Molluscum contagiosum (MC) is a common self-limiting poxvirus infection of the skin and occasionally mucous membranes. Lesions occur in children, usually on the trunk and body folds, and in young adults, if sexually transmitted, in the genital region. They typically present as multiple 1–10 mm diameter discrete, pearly white or flesh-colored umbilicated papules. They may be surrounded by an eczematous reaction, which disappears on resolution of the infection. Mollusca may be very extensive and recalcitrant to treatment in all forms of cell-mediated immunosuppression, especially in patients with AIDS.
There is no specific antiviral therapy for molluscum contagiosum. Physical and chemical destructive methods of treatment as well as topical and systemic immunostimulatory therapies have been tried, but no single intervention has been convincingly shown to be effective. Only a few have been subjected to the rigors of placebo-controlled studies, important for a condition that has a high spontaneous resolution rate.
The choice of therapy will depend on the age and immune status of the patient as well as the number and location of the lesions. In immunocompetent patients with few lesions it is reasonable to await spontaneous resolution, which will usually occur within a few months. Secondarily infected MC may need topical antiseptic or antibiotic treatment to minimize the risk of atrophic scarring. Active intervention may be justified for cosmetic reasons, or to hasten resolution, in order to prevent autoinoculation or transmission of the virus to close contacts. Avoidance of communal bathing and restriction of the sharing of towels should also help prevent the spread of infection to others.
A commonly used and inexpensive treatment is the manual extrusion of individual lesions using gloved fingers or fine forceps. This has proved more effective than cryotherapy applied every 3 to 4 weeks. Curettage and electrodesiccation of larger lesions may result in scarring and also requires pain alleviation, especially in children, by the prior application of a eutectic mixture of local anesthetics (lidocaine and prilocaine cream). Topically applied caustic agents have been used with variable results. Good success rates are reported with topical application of 40% silver nitrate paste, 0.5% podophyllotoxin, and 10% povidone-iodine with 50% salicylic acid. A useful alternative is 5% acidified nitrite, applied nightly with 5% salicylic acid under occlusion. Significant scarring has been documented with both potassium hydroxide and phenol, and the latter is no longer recommended. Although cantharidin has proved to be an effective treatment, it is not readily available in the UK and is not currently recommended by the Food and Drug Administration. The topical immune response modifier imiquimod has been shown to be effective and safe in several placebo-controlled studies. In patients with AIDS, both 1% imiquimod and topical cidofovir 3%, a competitive inhibitor of DNA polymerase, have proved successful for treating MC. Recovery of immune function with highly active antiretroviral therapy (HAART) may also result in the resolution of MC in these patients.
Methylene blue staining of a smear to look for molluscum bodies or histopathology of a curetted specimen
This is only required when the diagnosis is in doubt.
Hawley TG. J Hyg 1970; 68: 631–2.
Although the individual lesions of MC last 6 to 8 weeks, by autoinoculation the total duration of infection may be up to 8 months.
Weller R, O’Callaghan CJ, MacSween RM, White MI. Br Med J 1999; 319: 1540.
There was no difference in overall efficacy of the two methods, but phenol resulted in significantly more scarring.
Ormerod AD, White MI, Shah SAA, Benjamin N. Br J Dermatol 1999; 141: 1051–3.
A double-blind study in 30 children of sodium nitrite 5% co-applied nightly with 5% salicylic acid resulted in a cure rate of 75%, compared to 21% with salicylic acid alone.
Leslie KS, Dootson G, Sterling JC. J Dermatol Treat 2005; 16: 336–40.
One hundred and 14 children with MC were treated with 70% alcohol vehicle, phenol 10% or salicylic acid gel 12%. Salicylic acid was well tolerated and significantly better than the vehicle alone or phenol.
Ohkuma M. Int J Dermatol 1990; 29: 443–5.
Povidone-iodine solution 10%, and 50% salicylic acid plaster applied daily to MC in 20 patients was significantly more effective than either agent used alone, with a mean duration to clearance of 26 days and with no adverse effects.
Niizeki K, Hashimoto K. Pediatr Dermatol 1999; 16: 395–7.
In 389 patients topical 40% silver nitrate paste was applied after 2% lidocaine gel; 70% cleared after one application, 97.7% after three applications. Treatment was well tolerated and no scarring was reported. It was easier to apply than a 40% aqueous solution of silver nitrate.
Treatment of Skin Disease Comprehensive Therapeutic Strategies 4e
Await spontaneous resolution
Manual extrusion with gloved fingers or fine forceps
Topical 5% acidified nitrite co-applied with 5% salicylic acid
Topical salicylic acid gel 12%
Topical 10% povidone-iodine and 50% salicylic acid
Topical 40% silver nitrate paste
Topical 0.5% podophyllotoxin
Cryotherapy
