Dear Dr. Jeff: Is molluscum an STD? P.B
Dear P.B.: Molluscum contagiosum is a skin infection caused by a member of the pox virus family, Molluscipoxvirus (MCV), one of the largest DNA viruses known. Infection of skin cells causes a "bump" or papule to form, typically two to four millimeters in size (but ranging from one to 15 millimeters), typically "umbilicated" (dimpled in the middle), and initially firm, flesh-colored, pearl-like, and dome-shaped. The lesions are painless (though sometimes a little itchy), and are usually clumped together in groups. Older lesions may contain a pale, waxy core, much like a "blackhead."
Except in people who are immunocompromised (from HIV infection or e.g. chemotherapy), molluscum is a completely benign, self-limited infection of little medical consequence beyond its further spread.
Incubation of MCV averages two to three months, and ranges from a few weeks to more than six months. Untreated, molluscum lasts six to 12 months, or longer. Auto-inoculation (spreading MCV from one part of your body to another by scratching) is common.
Diagnosis of molluscum is made from their appearance, or by what radiologists sometimes call the "Aunt Bessie technique" (you recognize your Aunt Bessie as your Aunt Bessie because she looks like your Aunt Bessie). If uncertain, diagnosis can be confirmed by biopsy. Early genital lesions can look a lot like herpes or warts, but unlike herpes, MCV lesions are painless.
A variety of treatments for molluscum are available. Most involve removing the infected papules by freezing, burning, scraping, or chemical peeling. Others involve provoking and augmenting a localized immune response. Left alone, molluscum papules will eventually resolve on their own without leaving a scar. More aggressive treatments (especially surgical debridement) may remove the lesions sooner, but may also leave scars.
Preventing the spread of molluscum is pretty straightforward: no skin-to-skin contact with MCV lesions. Of course, this may prove challenging during the incubation period, when the virus is present but inapparent. If molluscum has infected genital skin, latex condoms will offer very effective protection against further spread.
Molluscum used to be most commonly seen in children, on the face, arms and legs, but has also come to be an infection not infrequently found in sexually active adults. MCV can infect "regular" skin as well as mucous membranes?in fact anywhere on the body except the palms and soles. Because it is spread via skin-to-skin contact, and is readily spread through intimate contact, molluscum is considered by some to be an STD. But what does that term really mean?
Sexually transmitted diseases are diseases that are spread by having sex with someone who has that STD. Many prefer the term Sexually Transmitted Infection, or STI, a broader concept than STD, which refers to infection with any pathogen that can cause a sexually transmitted disease, even if the infected person has no symptoms or signs (no obvious "disease") from the infection. And then there's the more useful concept of STI as a Sexually Transmissible Infection. According to Wikipedia, an STI "is an infection that has a negligible probability of transmission by means other than sexual contact, but has a realistic means of transmission by sexual contact." And so, for instance, meningitis, or the common cold, or molluscum contagiosum, are all transmissible through intimate contact, but should not be labeled STIs because sexual contact is neither the necessary nor the primary vector of spread from one person to another. There!
Be well!
Jeff Benson, MD
Dudley Coe Health Center