Review Question - QID 104269

The appearance of pearl-colored, grouped papules with a central umbilication is characteristic of molluscum contagiosum.

Molluscum is caused by a DNA poxvirus. It typically appears as firm, smooth, papules with a central umbilication and is typically pearl or flesh colored. They can be spread by direct contact, which is typically the mode of transmission in children. It can also be transmitted via sexual contact. When this is the case, the lesions tend to appear in the genital area and thighs. If a patient scratches and opens the lesions, they can be spread directly leading to a linear pattern. Extensive or prolonged infection is often associated with immunodeficiency.

Guirguis-Blake discusses treatment of molluscum contagiosum. Lesions will often resolve on their own following a period of local inflammation. However, removal by mechanical means is an appropriate option. Available methods include cryotherapy, topical agents such as tretinoin and cantharidin, and systemic treatment such as cimetidine.

Hanson and Diven discuss the epidemiology of molluscum contagiosum. While the condition is most common in children, it is more prevalent in areas with overcrowding, poor sanitary conditions, and high levels of poverty. In the past 30 years the incidence has been increasing as a sexually transmitted disease and among those with HIV. The worldwide incidence is 2% to 8%, but among those with HIV and have the DNA poxvirus, 5% to 20% present with lesions.

Figure A is an example of molluscum contagiosum on the face. Note the pearl-colored character of the lesion as well as the central umbilication. Illustration A demonstrates a clustering of molluscum contagiosum on the face. Again note the pearl coloring of the papules.

Incorrect Answers:
Answer 1: Milia are small, white-yellow epidermoid cysts 1-2mm in diamter. While they often occur on the face, there is no central umbilication.
Answer 3: Warts (verruca vulgaris) caused by human papillomavirus tend to be hyperkeratotic and verrucous, unlike the smooth appearance of molluscum contagiosum.
Answer 4: Sebaceous hyperplasia typically has a yellow appearance rather than the pearl colored appearance of molluscum contagiosum.
Answer 5: Keratoacanthomas tend to be solitary lesions with a keratin center. They also tend to be larger than molluscum contagiosum at 1 to 2 cm.