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NEWPORT BEACH, CALIF.– Desquamation is a handy way to differentiate between Staphylococcus skin infections and molluscum.
Most of the time, the presentation of molluscum “is straightforward, but it’s one of the great imitators,” according to pediatric dermatologist Dr. James Treat of the department of pediatrics at the Children’s Hospital of Philadelphia. Molluscum can present as pearly little drops, inflamed papules that look infected, or even a large cyst. Molluscum also can kick up a small patch of localized eczema that makes it easy to overlook pathognomonic signs, he said at Skin Disease Education Foundation’s Women’s & Pediatric Dermatology Seminar.
Dr. James Treat
Sometimes, patients wind up being treated for folliculitis, bug bites, and other problems they don’t have. “We see people who get multiple antibiotics. I’ve seen so many patients who have been told they have recurrent MRSA,” Dr. Treat said.
However, methicillin-resistant Staphylococcus aureus (MRSA) secretes a toxin that causes the nearby epidermis to slough off; molluscum does not. “That’s a nice little marker for a staph infection,” Dr. Treat noted. As for pruritus, “You sometimes see a child who presents with a random spot of eczema on an arm, leg, or an inguinal fold that they’ve never had before. Look for molluscum in the center of it. When in doubt, culture,” he said.
Lesions often become inflamed, which makes parents worry about infection, but “the reality is that molluscum is almost never infected. If you take a little blade or needle and pop into it, you are not going to get pus out,” Dr. Treat said.
Instead, inflammation is a sign that the body is attacking the virus, which “is a really good thing.” The phenomenon was recently dubbed the beginning-of-the-end (BOTE) sign. If kids come in with inflamed molluscum, it’s time to “talk parents off the ledge. The body has already done your job for you.” Dr. Treat said.
If the body hasn’t yet done it’s job, the goal of treatment is to irritate the lesion to draw the immune system’s attention to it.
Scraping is the most reliable one-time treatment, but the blood and pain are too much for small children. Salicylic acid and topical imiquimod do the job the first time around in about half of kids, and cantharidin in about a third, Dr. Treat said (Pediatr. Dermatol. 2006;23:574-9).
Freezing and comedone extraction work, too, but they hurt, so are best used in older, “highly motivated” children. Don’t overdo freezing either; it might cause pigment changes, said Dr. Treat.
Also, “it’s reasonable to treat those itchy, red patches” with a low-potency topical steroid “because that’s what’s making the kid uncomfortable,” he said.
Doing nothing is reasonable, too, because molluscum is self-limiting, but it’s wise to tell parents it can take as long as 2 or more years for the condition to burn itself out.
Whether or not observation is the treatment of choice, parents need to know that molluscum can spread through bathing with siblings, and via wet washcloths, bathing suits, towels, and pool toys. Wrestling, assisting other children in gymnastics, and other skin-on-skin activities can spread molluscum, too.
Parents also need to know that molluscum on the face can present as unilateral conjunctivitis. “A random red eye should be evaluated. This is where I might use oral cimetidine. It’s totally off label and has limited data, but it’s also over the counter and reasonable to try,” Dr. Treat said.
Dr. Treat has no relevant disclosures. SDEF and this news organization are owned by Frontline Medical Communications.