Medication Summary
Molluscum contagiosum usually resolves within months in people with a normal immune system. Many treatments have been promoted for molluscum contagiosum. The common goal of most treatment methods is the destruction of lesions and the development of a localized inflammatory reaction. Extensive controlled studies have not been performed and all treatments have advantages and disadvantages. A review for the Cochrane Database examined the effects of several topical, systemic, and homeopathic interventions. [29] One report suggested using a 10% solution of essential oil of Australian lemon myrtle (Backhousia citriodora). [63]
Among the findings, the investigators determined that there was limited evidence for the efficacy of sodium nitrite coapplied with salicylic acid compared with salicylic acid alone.
In addition, no statistically significant differences were found for topical povidone iodine plus salicylic acid compared with either povidone iodine or salicylic acid alone
The investigators also found no statistically significant differences between treatment with placebo and therapy with potassium hydroxide or between placebo treatment and systemic treatment with cimetidine or calcarea carbonica, a homeopathic drug.
The authors concluded no single intervention has been shown to be convincingly effective in treating molluscum contagiosum. However, various limitations were found in the studies reviewed, and the investigators cautioned that small study sizes may have caused some important treatment differences to be missed. None of the evaluated treatment options were associated with serious adverse effects.
Keratolytic Agents
Class Summary
These agents inhibit cell growth and destroy infected cells. They are applied directly to lesions. To decrease discomfort, treat a small number of lesions at each visit.
Salicylic acid (Compound W, Freezone, Wart-Off)
Salicylic acid produces desquamation and inflammation. Various liquid products that contain 17% salicylic acid as the caustic agent or as part of a mix of caustic agents used to treat molluscum contagiosum and warts are available. Most of these products include an adhesive such as collodion or a clear nail-polishlike material, which dries within seconds of application. This helps to concentrate the caustic agent on the lesion and minimize spread to the surrounding skin.
Tretinoin topical (Retin-A, Avita, Tretin-X)
Tretinoin is available in various bases and concentrations (0.025%, 0.05%, 0.1% cream; 0.01%, 0.025%, 0.1% gel; 0.05% solution). Applied to a region of skin with scattered lesions, tretinoin may produce eczema and increase the number of lesions through autoinoculation. However, a small amount of tretinoin may be applied to individual lesions with good effect.
Cantharidin
Cantharidin is a strong vesicant. It has not been approved by the FDA for the treatment of any condition but has been safely and effectively used by dermatologists for years. In the American Academy of Dermatology treatment guidelines for warts, it is listed as the second-line therapy following liquid nitrogen. However, because cantharidin has never been approved by the FDA for use in humans, it is no longer marketed in the United States.
Cantharidin crystals and diluent can be purchased in the United States, and numerous dermatologists continue to use it. Cantharidin solution for the treatment of warts and molluscum is available in Canada and many other countries. The effectiveness results from the exfoliation of the lesion as a consequence of cantharidin's vesicant action. The lytic action does not go below the basement membrane of epidermal cells. As a result, unless the area becomes secondarily traumatized or infected, no scarring from topical application occurs.
Topical Skin Products
Class Summary
These agents induce cytokines, including interferon. They are typically reserved for use in patients with molluscum contagiosum that is refractory to cryotherapy or tretinoin.
Antivirals, Other
Class Summary
Presumably, antiviral drugs may interfere with the ability of the molluscum contagiosum virus to replicate. Because of their expense and adverse effect potential, consider these products for use only in immunocompromised patients.
Cidofovir (Vistide)
Cidofovir is a selective inhibitor of viral DNA production in cytomegalovirus and other herpes viruses. One case report showed improvement in 3 out of 3 patients with HIV and extensive co-infection with molluscum contagiosum virus.
Ritonavir (Norvir)
Ritonavir is an antiretroviral protease inhibitor. In one case report, a patient with HIV and intractable molluscum contagiosum had resolution of lesions after treatment.
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Note the central umbilication in these classic lesions of molluscum contagiosum.
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Approximately 10% of patients develop eczema around lesions. Eczema associated with molluscum lesions spontaneously subsides following removal.
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Molluscum contagiosum on the shaft of the penis. Molluscum contagiosum in the genital region of adults is most commonly acquired as a sexually transmitted disease.
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Larger lesions may have several clumps of molluscum bodies rather than the more common single central umbilication. This may make them difficult to recognize as molluscum contagiosum.
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Molluscum lesions may become quite numerous in intertriginous areas. This child has autoinoculated lesions to both inner thighs.
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After trauma, or spontaneously after several months, inflammatory changes result in suppuration, crusting and eventual resolution of the lesion. This inflammatory stage does not usually represent secondary infection and seldom requires antibiotic therapy.
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Lesions of molluscum contagiosum have a characteristic histopathology. Lobules containing hyalinized molluscum bodies, also known as Henderson-Paterson bodies, are diagnostic.
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This lesion of cutaneous coccidioidomycosis could be included among the differential diagnoses of molluscum contagiosum.
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This keratoacanthoma could be included among the differential diagnoses of molluscum contagiosum.
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Lesions on the upper eyelid of a 3-year-old child.
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In a patient who had preexisting molluscum contagiosum, the virus was inoculated along a line of minor skin trauma, resulting in the development of the 3 new lesions.
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Molluscum contagiosum on the right axilla.
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Presented here are the classic umbilicated papules of molluscum contagiosum lesions on the cheek of a child. Facial lesions occur frequently in children, although lesions generally are few.
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Molluscum contagiosum rarely occurs on the face in an adult unless the patient is infected with HIV. When molluscum contagiosum occurs in individuals infected with HIV, facial lesions are common and frequently numerous.
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Molluscum contagiosum lesions in individuals infected with HIV may number in the hundreds. In addition, they may become quite large and prominent.
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This low-power view of a molluscum contagiosum lesion shows the classic cup-shaped invagination of the epidermis into dermis. The Henderson-Paterson bodies are identified readily and stained purple to red in this image.
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This is a medium-power view of a molluscum contagiosum lesion. Magnification allows better demonstration of the intracytoplasmic molluscum bodies (staining purple-pink) within the keratinocytes.
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This molluscum contagiosum body is an intracytoplasmic inclusion body. Notice in the image that the keratinocyte nuclei are displaced to the periphery of the cell and that the intracytoplasmic inclusions have a granular quality.
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Multiple papules on the face of a man with HIV.
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Cytoplasmic viral inclusions become progressively larger toward the epidermal surface (hematoxylin and eosin, 200X)
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Low-power histopathologic examination reveals an overall cup-shaped appearance.
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Viral particles have a dumbbell-shaped appearance. Courtesy of Alvin Zelickson, MD.
