Molluscum Contagiosum

THE CASE:

A 40-year-old womanwith HIV infection has had an occasionallypruritic facial rash for severalmonths. The rash is not associatedwith any systemic symptoms.

Which of the following seemsthe most likely cause of the rash?

• Herpes simplex
• Molluscum contagiosum
• Verruca plana (flat warts)

DISCUSSION:

The patient hasmolluscum contagiosum, a benignDNA poxvirus infection that usuallyremains localized in the epidermis.Patients do not exhibit systemicsigns and symptoms, although, onoccasion, lesions may become secondarilyinfected. Children and immunocompromisedpatients (ie, thosewho are immunosuppressed orHIV-positive or who are taking corticosteroids)may exhibit more extensivelesions.

Transmission is primarily by directcontact, including sexual contact.The typical lesions are pearly to fleshcolored,smooth, dome-shaped papulesthat develop a soft, indented core(umbilication). The 2- to 6-mm lesionsmay appear anywhere on the body,although they rarely involve the palms,soles, or mouth. Large, disfiguringlesions may develop in immunocompromisedpatients, especially thosewith HIV disease.

The diagnosis is usually made clinically, based on thelesions' distinctive appearance. Treatment is not mandatory,because the lesions generally resolve spontaneouslyand heal without scarring, unless secondary infection hasoccurred. Treatment methods include curettage, cauterization,cryotherapy, and application of such topical preparations as podophyllotoxin cream, trichloroacetic acid, andcantharidin. Genital lesions are treated in order to minimizespread by sexual contact.

Without treatment, lesions may persist from 2 to12 months. The lesions of immunocompromised patientsmay persist for years. Reinfection may occur.

This patient had been treated with a variety of medications,none of which cleared the lesions-presumablybecause of her persistently elevated viral load.

Other entities in the differential. The lesions ofherpes simplex virus (HSV) infection consist of clusteredvesicles on an erythematous base (Figure 1). The vesiclesevolve to pustules or ulcerated lesions, which eventuallyform a crust. Recurrence at or near the same site iscommon, especially along the distribution of a sensorynerve. Patients with primary lesions usually have associatedsystemic symptoms, including malaise, fever, and generalizeddiscomfort. HSV-1 lesions erupt above the waist,especially in the perioral region (herpes labialis). HSV-2lesions generally occur in the genital area.

Although most HSV infections are self-limited, theuse of antiviral therapy may reduce the duration of symptomsand help prevent transmission and dissemination.Herpes labialis is usually treated with oral acyclovir, valacyclovir,or famciclovir. Topical agents are available butare thought to be less effective than oral medications.

Verruca plana (flat warts) are lesions caused by theDNA-containing human papillomavirus, of which there aremany types (Figure 2). Flat warts typically develop onthe face and backs of the hands as small individual papulesof approximately one-quarter inch in diameter. Wartsare common in children, usually between the ages of12 and 16 years, although they may occur in adults. Infectionoccurs either by direct contact with an infected personor after direct contact with the virus, which may remainviable in a warm, moist environment. In most cases,warts disappear spontaneously within 6 months to 3 years;however, recurrence is common. Warts may be removedby a number of techniques, including laser therapy, surgery,and application of liquid nitrogen.