LAS VEGAS – Although molluscum contagiosum is harmless, it can be confused with warts or lesions commonly related to herpes and various types of acne.
“Molluscum contagiosum really is one of the great imitators,” Dr. James Treat said at a pediatric update sponsored by the American Academy of Pediatrics California District 9. “They can be great big cysts, and they can be tiny ditzels; you can barely tell they’re there. They also can be more classic, umbilicated papules.”
Dr. James Treat
Clinicians can make a quick diagnosis by angling an otoscope to the side of the lesion, said Dr. Treat. Once illuminated, “You’ll see this tiny white spicule at the center of the lesion. That’s a great way of diagnosing it.”
Children and adolescents often present with inflamed, painful lesions, prompting concern from parents. In fact, Dr. Treat identified a recent article naming inflamed molluscum lesions as the BOTE sign: the beginning of the end (Pediatrics 2013; 131:e1650-3). “If your spots are getting red, your body knows the virus is there,” he said. “You don’t have to do anything else about it. They’re almost never infected. It’s just like an ingrown hair. It can look like a pus bump; you get inflammation; it’s a little bit painful. They’re usually just inflamed. If you think someone truly has cellulitis, of course, give them antibiotics. But the majority [of lesions] are not infected.”
When in doubt, culture the lesion. “If you grow streptococcus or staphylococcus, then you know you need to treat them,” he said. “If you grow normal skin flora, though, don’t be surprised. That’s what’s most commonly going to happen. It’s similar to acne or an ingrown hair.”
The time course for complete clearance of molluscum is usually 1-2 years. “It’s probably a bit shorter than that, but it’s better to underpromise,” said Dr. Treat, a pediatric dermatologist at Children’s Hospital of Philadelphia.
No Food and Drug Administration–approved treatment options for molluscum exist, Dr. Treat noted. For lesions under the armpit, for example, he often recommends treating associated dermatitis with hydrocortisone and applying moisturizer to the lesions until they resolve, he said. However, most parents want other treatment options, especially if their child competes in wrestling or other contact sports. His preferred treatment is cantharone, also known as “beetle juice.” Clinicians apply the liquid cantharone solution directly to the lesions in the office, and instruct the parents to help the child wash off the solution after 2 hours. The treatment causes blistering and ultimate breakdown of the molluscum.
“Some centers are not allowing clinicians to use cantharone, because it never went through FDA approval,” Dr. Treat said. “I never use it on the face, around the eye, or inside the diaper area. I put a tiny drop on, and instruct them to wash it off after 2 hours.”
Cryotherapy is another option, though Dr. Treat advised caution. “I think you can do it if you have a motivated teenager who wants their five spots gone very quickly, or if you have a young child that has a couple of spots on the cheek and you can hold them very still and freeze very lightly to get those spots to go away,” he said. “I would not perform cryotherapy around the eye. You have to be careful with cryotherapy because it hurts, and you can cause more inflammation than you really expected, or a blister, for something that’s benign and is going to go away on its own. But there’s definitely a role for cryotherapy for a kid who needs to wrestle very soon or get back to sports, or has lesions in areas where you can’t control the cantharone.”
Curettage also may be used, Dr. Treat said, although “it’s not something we commonly do unless you have a very motivated 10-, 12-, or 14-year-old who can stay still, or unless you have a child that has one or two spots located in a difficult area to treat otherwise,” he noted. Topical options include tretinoin. “I don’t think it works very well, but it’s something to do, and it’s been used on the faces of children,” said Dr. Treat. He recommended using a Q-tip swab to apply a pinhead-sized amount of tretinoin to individual lesions. “Try not to treat the skin around it,” he advised. “Your goal is irritation of the lesion; you are trying to irritate the skin to get the immune system to notice the molluscum.” He characterized sinecatechins as “expensive and often irritating” and considers oral cimetidine as a “last-ditch effort” for patients with molluscum lesions all over the body. “It works 20-30% of the time,” he said. “You have to take it two to three times a day, and you have to take it at the high end of the normal dosing range. But there are some data that show that in patients with bad atopic dermatitis who have terrible molluscum, it might work.”