Molluscum Contagiosum

Caused by a poxvirus

The lesions are autoinoculable and spread by wet skin-to-skin contact

In sexually active individuals, lesions may be confined to the penis, pubis, and inner thighs and are considered a sexually transmitted infection

Common in AIDS patients

• Usually with a helper T cell count < 100/mcL

• Extensive lesions tend to develop over the face and neck as well as in the genital area

• Lesions are difficult to eradicate unless immunity improves, in which case spontaneous clearing may occur

Presents as single or multiple, dome-shaped, waxy papules 2–5 mm in diameter that are umbilicated

Lesions at first are firm, solid, and flesh colored but on reaching maturity become soft, whitish, or pearly gray and may suppurate

The principal sites are the face, lower abdomen, and genitals

Individual lesions persist for about 2 months

Clinical; based on the distinctive central umbilication of the dome-shaped lesion

Differential diagnosis

• Warts

• Varicella (chickenpox)

• Basal cell carcinoma

• Lichen planus

• Smallpox

• Cutaneous cryptococcosis (in AIDS)

The best treatment is by curettage or applications of liquid nitrogen as for warts but more briefly

When lesions are frozen, the central umbilication often becomes more apparent

Light electrosurgery with a fine needle is also effective

Cantharidin (applied in the office and then washed off by the patient 4 hours later) is a safe and effective option

Other treatment options

• Potassium hydroxide 10% solution applied twice daily until lesions clear

• Salicylic acid

• Podophyllotoxin

• Tretinoin

• Imiquimod

• Pulsed dye laser

• Comedone extractor or currette