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The findings of smooth, waxy umbilicated papules as seen in our case are characteristic of molluscum contagiosum. The patient was also diagnosed with human immunodeficiency virus infection with low CD4⁺T-cell counts. A regression of the skin lesions was seen after commencement of highly active antiretroviral therapy.

Molluscum contagiosum is a viral disorder of the skin characterized by discrete, single or multiple, flesh-colored papules. It is caused by Molluscipoxvirus, a large, double-stranded-DNA virus belonging to the same family as cowpox and smallpox.¹There are 4 subtypes, all of which behave clinically identically. Subtype I (75%-90% of cases) is the most common, followed by subtype II.²

Molluscum contagiosum occurs in 2% to 8% of immunocompetent children and in 10% to 20% of human immunodeficiency virus–positive patients; the prevalence in patients with human immunodeficiency virus infection is directly related to the degree of immunocompromise. Since the introduction of highly active antiretroviral therapy, the number of molluscum contagiosum cases in patients with AIDS has decreased significantly.

Molluscum contagiosum is spread by direct skin-to-skin contact and can occur anywhere on the body. Transmission of Molluscipoxvirusin children is thought to occur by intimate skin-to-skin contact or through fomites such as bath sponges and towels, contact sports, or autoinoculation. It can be associated with atopic dermatitis, possibly because of autoinoculation due to scratching. Like smallpox, the only known host for molluscum contagiosum is humans. The average incubation time for Molluscipoxvirusis between 2 and 7 weeks but can be as long as 26 weeks.¹

The typical lesions are smooth, firm, umbilicated, spherical papules about 1 to 20 mm in diameter. They can be white, flesh colored, translucent, yellow, pink, or red (especially when irritated). The characteristic appearance of these lesions is usually diagnostic. Occasionally, they can be polypoid with a stalk attached to the skin. Giant lesions of up to 1.5 cm are seen more often in immunocompromised patients.³There are usually fewer than 30 lesions, although several hundred have been reported; large numbers of lesions may coalesce to form a plaque. The most distinctive feature of molluscum contagiosum is the central umbilication. In children, molluscum contagiosum seems to mostly affect the limbs, particularly involving the antecubital and popliteal fossae, crural folds, and torso. The face and neck are commonly affected in immunocompromised patients. The palms and soles are characteristically spared.

In immunocompetent patients, lesions usually spontaneously resolve around puberty. Persistent lesions may require treatment. Treatment options include mechanical destruction and immunomodulator therapy. Mechanical destruction can be achieved by freezing, burning, application of topical acids, curettage, electrodessication, or laser therapy. Results using acids usually take weeks to months. One of the most common, quick, and efficient methods of treatment is cryotherapy. Liquid nitrogen, dry ice, or dichlorotetrafluoroethane is applied to each individual lesion for a few seconds. Repeat treatments at 3 to 4 weeks may be required. Recurrence may be seen in about one-third of patients. Pulsed dye laser therapy has been used with 96% clearance with a single treatment.⁴In a series by Binder et al,⁵84.3% of patients had resolution with a single laser treatment with no recurrence, 10.5% required an additional treatment, and 5.2% had resolution with 3 treatments. Reappearance of molluscum contagiosum papules may signify ongoing disease exacerbation, reinfection, or a rebound from latency. For patients with impaired immune functions or widespread eruptions, local therapies are usually ineffective and antiviral and immunomodulatory medications must be used. Immunomodulator therapy includes topical, injected, or systemic agents. Imiquimod (administered as a topical 5% cream) acts by inducing interferon α and other cytokines that enhance the host's cellular immune response and help combat the primary viral infection.⁶Its efficacy has been between 33% in patients completing 4 weeks of daily treatment with imiquimod⁷and 69% in patients receiving 4 months of thrice weekly treatment.⁸Injectable agents such as interferon α have been used subcutaneously and intralesionally with some effect in recalcitrant molluscum contagiosum.⁹Topical antivirals such as cidofovir, 3%, have been used, with clearing seen in 2 to 6 weeks.¹⁰

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Correspondence:Sunita Juliana Ferns, MD, Department of Pediatrics, University of Illinois at Chicago, 840 S Wood St, Chicago, IL 60612 (sjulianaferns@yahoo.com).

Accepted for Publication:September 15, 2008.

Author Contributions:Study concept and design: Ferns. Acquisition of data: Ferns. Analysis and interpretation of data: Ferns and Noronha. Drafting of the manuscript: Ferns. Critical revision of the manuscript for important intellectual content: Ferns and Noronha. Administrative, technical, and material support: Ferns.

Financial Disclosure:None reported.