MIAMI BEACH Treatment of molluscum contagiosum can be guided by patient age, lesion location, cosmetic considerations, and the anxiety of the parent and patient, according to two presentations at the annual Masters of Pediatrics conference sponsored by the University of Miami.
"Most warts and molluscum [lesions] go away on their own," Dr. Lawrence Schachner said. "But most of the time, you cannot talk parents into just waiting for a year. They want something done."
Physicians can destroy lesions on the body by using cantharidin, or on the face by using trichloroacetic acid (TCA). Curettage, cryotherapy, and sensitization with squaric acid are other office-based options. Topical treatments and systemic cimetidine are among the home-based strategies, said Dr. Schachner, professor of pediatrics and dermatology and chairman of dermatology at the University of Miami.
"Molluscum treatment varies considerably with the doctor you go to," Dr. Bernice Krafchik, professor emeritus at the University of Toronto, said during a separate presentation at the meeting. "Every doctor believes their treatment is the best."
Lesions are typically 15 mm, discrete, shiny, and pearly. "You will always see umbilication and a domed papule if you look, which makes it easy for the differential [diagnosis]," Dr. Schachner said. Incubation takes 28 weeks, and spontaneous resolution can take up to 2 years. Molluscum contagiosum accounts for approximately 280,000 physician visits annually (Pediatr. Dermatol. 2004;21:62832).
Molluscum contagiosum can be spread by skin-to-skin contact, fomites, autoinoculation, or warm pool or bath water. "It also can be an STD in sexually active adolescents or adults," Dr. Schachner said.
"Do no harm," Dr. Krafchik asserted. "I treat molluscum but I don't treat warts. The treatment of molluscum is relatively easy, and you see a lot of inflammation if you leave them alone."
For both Dr. Schachner and Dr. Krafchik, topical cantharidin (an extract from the blister beetle) is the treatment of choice for young children with widespread lesions. It should be initially applied using the blunt end of a cotton-tipped swab or a toothpick to a few lesions. "Do not use it on 25 lesions the first time … because some children are hyperreactors," he added. Cover the treated area with a bandage and soak it off in a bath 34 hours later.
Warn parents that bullae can form on treated lesions, Dr. Krafchik said. She instructs parents to leave the blisters alone; however, if the blisters are painful, parents can drain them with a sterile needle and apply an over-the-counter topical antibiotic. Cantharidin cleared the lesions in 90% of 300 children after an average of 2.1 visits in a retrospective study (J. Am. Acad. Dermatol. 2000;43:5037).
"My conclusion is it is safe and effective," Dr. Schachner said. "But it's an office technique. I would never send a patient home with some cantharidin."
TCA for face or neck lesions is another office-based treatment option. Start at 25% strength and increase as tolerated, Dr. Schachner said.
He did not recommend the use of topical tretinoin or keratolytics for molluscum contagiosum, but imiquimod (Aldara) can be used to treat a limited number of lesions. The agent "works pretty well, but it's awfully irritating anywhere skin may rub on skin," Dr. Schachner said, adding that "it is not my first choice, but it is a choice. It's a little expensive."
"Remember, Aldara is very expensive," Dr. Krafchik said. "Parents get peeved when they come back to your office."
Curettage can be very effective and yields immediate results. "If you put a little nick in it and squeeze it, the viral core will come out," Dr. Schachner said. Curettage is generally reserved for older children with a limited number of lesions.
Dr. Krafchik said that she no longer performs curettage on molluscum contagiosum lesions because "it always bleeds and kids hate the sight of blood." A meeting attendee said that one lesion is easy to remove. "You're right," Dr. Krafchik replied. "It is easy to remove one molluscum … and it's quite a different thing when there are many."
Cryotherapy is another consideration in older children, particularly if the lesions are large or located on the face or neck, Dr. Schachner said. A cotton-tipped application of liquid nitrogen for a 5- to 10-second freeze, repeated at 2- to 4-week intervals, can be effective, but pain, blistering, scarring, and dyspigmentation are potential adverse events.
"Regarding liquid nitrogen: I don't use [it] in children as a rule," Dr. Krafchik said. "It's very painful and you cannot use it long enough to get a good result. It's not fair to the kids."