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John Jesitus is a medical writer based in Westminster, CO.
Hand sanitizers represent a new and perhaps underappreciated category of cosmeceutical, according to Zoe Draelos, M.D., a High Point, N.C., dermatologist in private practice and consulting professor, department of dermatology, Duke University School of Medicine, Durham, N.C.
Boston – Hand sanitizers represent a new and perhaps underappreciated category of cosmeceutical, according to Zoe Draelos, M.D., a High Point, N.C., dermatologist in private practice and consulting professor, department of dermatology, Duke University School of Medicine, Durham, N.C.
“Many dermatologists haven't thought much about hand sanitizers, but this product category carries a lot of dermatologic significance,” Dr. Draelos said at the 2012 American Academy of Dermatology Summer Academy Meeting.
The federal government says hand sanitizers have been responsible for a worldwide decrease in the activity of many influenza strains, Dr. Draelos says. "Hand sanitizers differ from soap in that soap is not regulated by the Food and Drug Administration. Soap is the only product that doesn't fall under any government guidelines,” she says.
Conversely, she says the FDA considers hand sanitizers to be over-the-counter drugs. "Most products on the market are based on ethanol. These products are highly effective at killing germs. They evaporate quickly, but they are also very drying to the hands,” she says. “Therefore, many medical personnel and other frequent users of hand sanitizers wind up in dermatologists' offices with hand eczema.”
Thoughts on triclosan
Other antibacterial soaps contain triclosan. "Triclosan is more controversial. The FDA has expressed some concern that triclosan is very important to health in this country as a surgical disinfectant. But in the laboratory, it has been possible to make triclosan-resistant Escherichia coli,” Dr. Draelos says.
Accordingly, she says the government has announced that it is considering limiting the use of triclosan, which is found in everything from antibacterial bar soaps to toothpastes designed to prevent gingivitis. Fortunately, she says, "The triclosan-resistant organism was not long-lived. That's why we haven't seen triclosan-resistant organisms in the general population."
Mechanisms of action
Mechanistically, "Hand sanitizers were thought to function by blowing apart the bacteria, damaging the cell wall,” Dr. Draelos says. “It was believed that organisms could not develop resistance to them."
However, she says, scientists now know that ethanol actually dries up, desiccates and destroys the bacteria, a mechanism that cannot generate resistance. "But triclosan inhibits the production of lipids in the cell wall. And if an antibacterial agent has a specific target, it's possible for the bacteria to mutate to that target,” she says.
The only problem with popular ethanol-based hand washes is their flammability, Dr. Draelos says. "In operating-room situations where you're using cautery or other electrical devices that can create a spark, you cannot use ethanol-based products," she says. Benzalkolines are safe and effective in these situations, she adds.
Disclosures: Dr. Draelos reports no relevant financial interests.
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