Cantharidin Called Best Molluscum Treatment

VAIL, COLO. — Many pediatric dermatologists have begun to treat molluscum contagiosum with cantharidin, a blistering agent produced by a beetle, instead of with liquid nitrogen.

The reason they have switched is that cantharidin is much less painful and very well tolerated, Dr. Lawrence F. Eichenfield said at a meeting sponsored by the American Academy of Pediatrics.

“It has been shown in a variety of studies [to be] a highly effective agent,” said Dr. Eichenfield, a pediatric dermatologist at the University of California, San Diego, and Rady Children's Hospital, also in San Diego. The majority of the time, he said, one to three 4-hour applications are sufficient to treat the lesions. Cantharidin “is much less painful and traumatizing than either curettage or liquid nitrogen.”

Molluscum lesions resolve within 8 months 70% of the time, but if one decides to treat, then cantharidin is the treatment of choice, Dr. Eichenfield said.

He uses the method made popular by a report in 2000 from investigators at Northwestern University, Chicago—a method he has begun to teach to pediatricians.

In their report, the Northwestern investigators said they had treated 300 patients with cantharidin and later interviewed their parents. The researchers said that, with an average of two treatments, 90% of the patients were cleared of their lesions. Another 8% had improvement but were not cleared by the treatment, although their lesions resolved afterward (J. Am. Acad. Dermatol. 2000;43:503–7).

About 92% of the patients experienced blistering, and 37% reported erythema at the site after treatment, which lasted for up to 3 weeks. A total of 14% reported mild to moderate pain after treatment and 10% reported a transient burning sensation. Other adverse events—including pruritus (6%) and bleeding (1%)—occurred less frequently. There were no serious events.

When the parents were interviewed, 95% said they would have their child treated the same way again. Of the 14 who said they would not, three gave their child's blistering as the reason and one mentioned pain. The others said they did not find the multiple visits convenient or did not give a reason.

In the Northwestern method used by Dr. Eichenfield, the cantharidin (0.7% concentration) is daubed on the lesions with the wooden end of a cotton-swab, sparing the surrounding skin. He treats no more than 20 lesions at a time; he does not treat facial lesions with this method.

The sites are not occluded afterward, and the agent is washed off with soap and water 4–6 hours later, Dr. Eichenfield said.

The treatment is relatively safe, but he recommends physicians be trained before using cantharidin. “If not done appropriately, you can get very severe blisters.”

Cantharidin 'is much less painful and traumatizing than either curettage or liquid nitrogen. DR. EICHENFIELD

VAIL, COLO. — Many pediatric dermatologists have begun to treat molluscum contagiosum with cantharidin, a blistering agent produced by a beetle, instead of with liquid nitrogen.

The reason they have switched is that cantharidin is much less painful and very well tolerated, Dr. Lawrence F. Eichenfield said at a meeting sponsored by the American Academy of Pediatrics.

“It has been shown in a variety of studies [to be] a highly effective agent,” said Dr. Eichenfield, a pediatric dermatologist at the University of California, San Diego, and Rady Children's Hospital, also in San Diego. The majority of the time, he said, one to three 4-hour applications are sufficient to treat the lesions. Cantharidin “is much less painful and traumatizing than either curettage or liquid nitrogen.”

Molluscum lesions resolve within 8 months 70% of the time, but if one decides to treat, then cantharidin is the treatment of choice, Dr. Eichenfield said.

He uses the method made popular by a report in 2000 from investigators at Northwestern University, Chicago—a method he has begun to teach to pediatricians.

In their report, the Northwestern investigators said they had treated 300 patients with cantharidin and later interviewed their parents. The researchers said that, with an average of two treatments, 90% of the patients were cleared of their lesions. Another 8% had improvement but were not cleared by the treatment, although their lesions resolved afterward (J. Am. Acad. Dermatol. 2000;43:503–7).

About 92% of the patients experienced blistering, and 37% reported erythema at the site after treatment, which lasted for up to 3 weeks. A total of 14% reported mild to moderate pain after treatment and 10% reported a transient burning sensation. Other adverse events—including pruritus (6%) and bleeding (1%)—occurred less frequently. There were no serious events.

When the parents were interviewed, 95% said they would have their child treated the same way again. Of the 14 who said they would not, three gave their child's blistering as the reason and one mentioned pain. The others said they did not find the multiple visits convenient or did not give a reason.

In the Northwestern method used by Dr. Eichenfield, the cantharidin (0.7% concentration) is daubed on the lesions with the wooden end of a cotton-swab, sparing the surrounding skin. He treats no more than 20 lesions at a time; he does not treat facial lesions with this method.

The sites are not occluded afterward, and the agent is washed off with soap and water 4–6 hours later, Dr. Eichenfield said.

The treatment is relatively safe, but he recommends physicians be trained before using cantharidin. “If not done appropriately, you can get very severe blisters.”

Cantharidin 'is much less painful and traumatizing than either curettage or liquid nitrogen. DR. EICHENFIELD

VAIL, COLO. — Many pediatric dermatologists have begun to treat molluscum contagiosum with cantharidin, a blistering agent produced by a beetle, instead of with liquid nitrogen.

The reason they have switched is that cantharidin is much less painful and very well tolerated, Dr. Lawrence F. Eichenfield said at a meeting sponsored by the American Academy of Pediatrics.

“It has been shown in a variety of studies [to be] a highly effective agent,” said Dr. Eichenfield, a pediatric dermatologist at the University of California, San Diego, and Rady Children's Hospital, also in San Diego. The majority of the time, he said, one to three 4-hour applications are sufficient to treat the lesions. Cantharidin “is much less painful and traumatizing than either curettage or liquid nitrogen.”

Molluscum lesions resolve within 8 months 70% of the time, but if one decides to treat, then cantharidin is the treatment of choice, Dr. Eichenfield said.

He uses the method made popular by a report in 2000 from investigators at Northwestern University, Chicago—a method he has begun to teach to pediatricians.

In their report, the Northwestern investigators said they had treated 300 patients with cantharidin and later interviewed their parents. The researchers said that, with an average of two treatments, 90% of the patients were cleared of their lesions. Another 8% had improvement but were not cleared by the treatment, although their lesions resolved afterward (J. Am. Acad. Dermatol. 2000;43:503–7).

About 92% of the patients experienced blistering, and 37% reported erythema at the site after treatment, which lasted for up to 3 weeks. A total of 14% reported mild to moderate pain after treatment and 10% reported a transient burning sensation. Other adverse events—including pruritus (6%) and bleeding (1%)—occurred less frequently. There were no serious events.

When the parents were interviewed, 95% said they would have their child treated the same way again. Of the 14 who said they would not, three gave their child's blistering as the reason and one mentioned pain. The others said they did not find the multiple visits convenient or did not give a reason.

In the Northwestern method used by Dr. Eichenfield, the cantharidin (0.7% concentration) is daubed on the lesions with the wooden end of a cotton-swab, sparing the surrounding skin. He treats no more than 20 lesions at a time; he does not treat facial lesions with this method.

The sites are not occluded afterward, and the agent is washed off with soap and water 4–6 hours later, Dr. Eichenfield said.

The treatment is relatively safe, but he recommends physicians be trained before using cantharidin. “If not done appropriately, you can get very severe blisters.”

Cantharidin 'is much less painful and traumatizing than either curettage or liquid nitrogen. DR. EICHENFIELD