Molluscum Contagiosum - Worst Disease Name Ever?
After my first year of college, I got a summer job doing research at a university in my hometown. The task was to analyze a virus called molluscum contagiosum using a special yeast cell test. I had never heard of the virus before, but I quickly realized that friends tended to keep their distance when I brought it up that summer. (I would use that lesson to NOT publicize the work I did the next few summers with a particularly nasty strain of herpes virus.)
Molluscum contagiosum is a pretty awful name, because it sounds like a medieval plague. But it’s so common that hardly a week goes by when I don’t see it. And somehow it’s one of those things that most parents don’t know about. So I want to prepare you for the horror, the terror, of molluscum – actually, it’s mostly benign, but it falls into that common category of stuff that’s not really harmful but super annoying and hard to get rid of (I’m looking at you, ringworm.)
How do kids get it?
Molluscum is caused by a virus just like warts. It enters your child’s skin through tiny little “microabrasions,” which all kids have plenty of. Like most skin conditions, it’s more common in kids with eczema who tend to scratch a lot. Kids can pick the virus up from surfaces that other kids with molluscum have touched like playmats, or from direct contact with infected kids. It’s common for it to spread to siblings as well. After an incubation period that can last from weeks to months, kids develop the characteristic bumps.
What does it look like?
Molluscum bumps are pretty unique – they can range from pinpoint up to the size of a pencil eraser, and they’re “perfect.” By that I mean very smooth, skin-colored, and shaped like little round domes. Bumps from irritation or bites are red, whereas bumps from warts are rough like cauliflower and often have “seeds” visible inside them (really the ends of blood vessels). One last big hint is that the bumps tend to be “umbilicated,” which means they have a little “belly button” or dimple in the middle of the dome.
The bumps can occur anywhere on the body, but I see them most often on the sides of the torso and the thighs. There are almost always multiple bumps, often about 10, that cluster fairly close to one another. They are usually not painful or itchy. They’re superficial and rarely cause any permanent scarring. In kids with normal immune systems, the only way that molluscum bumps can hurt kids is if they get infected – I see this most often in kids with eczema who dig at their skin a lot.
One important note – when molluscum is finally about to go away, the bumps tend to turn more reddish and swell a bit. So they can look like they’re getting infected, but it’s a good thing!
So how do we make molluscum go away? That’s where it gets complicated, and a bit frustrating. The good news is that molluscum nearly always goes away on its own. The bad news is that this usually takes 6-9 months. One study found that the bumps went away on their own in 94.5% of kids within 6 ½ months after they appeared. (1) We do have treatments that work fairly well, but they’re not super pleasant for kids and are therefore tough to justify for a self-resolving condition. Even though warts are very similar, we treat them more aggressively because they are more destructive to skin, less likely to self-resolve, and more likely to cause pain. We want to get rid of those as quickly as possible.
What can you do at home?
To be clear, there is no proven home remedy to cure molluscum. But there are plenty that parents swear by. The general principle is that if you put something on the bumps that slightly irritates them, your immune system perks up and attacks the bumps a bit more vigorously. So feel free to rub a little apple cider vinegar, tea tree oil, or chalky toothpaste (think the classic light-blue Crest) on your kid’s bumps.
There are really only three reasons to get molluscum treated by a doctor:
1. They spread to the face – these become more of a cosmetic issue and can start to spread even more rapidly since kids touch their faces lot.
2. They’re multiplying like crazy – occasionally molluscum can explode within a few weeks to over 50 bumps! That definitely merits a trip to the doctor.
3. They’re getting infected – this is most likely in kids with eczema, who tend to scratch a lot. The bumps get red, larger, and painful, and can have some crusting or discharge as well.
What can the doctor do?
If molluscum needs treatment, most pediatricians will send kids to a dermatologist. The most common treatment here in the U.S. is cantharidin. Cantharidin is a chemical isolated from “blister beetles,” and it causes the bumps to separate from the rest of your skin. One study found that 90% of kids treated with cantharidin were cleared with an average of 2 treatments. (2) And 95% of the parents in the study were satisfied and would be willing to get the treatment again in the future. Other options are a bit less exciting. Freezing with liquid nitrogen is painful and can cause scarring and “curettage,” or “cutting them off” (the treatment of choice in the Netherlands, by the way) has some obvious disadvantages.
So the bottom line? Be able to identify molluscum, but don’t worry too much about it. Realize that most of the time the treatment is worse than the bumps themselves, and that they’ll usually go away on their own. And when your friends ask about the bumps, if you want your kids to have a social life, take it from me and leave out the “contagiosum” part.
1. Takemura T, Ohkuma K, Nagai H, et al. The natural history of molluscum contagiosum. Examination Treatment Dermatol Dis (Japanese). 1983;5(7): 667-70.
2. Silverberg NB, Sidbury R, Mancini AJ. Childhood molluscum contagiosum: experience with cantharidin therapy in 300 patients. J Am Acad Dermatol. 2000 Sep;43(3):503-7.