Onion extract offers treatment for scars

February 1, 2005

National report — Anecdotal evidence indicates that the onion extract/allantoin gel product Mederma (Merz Pharmaceuticals) might be an effective first-line therapy for diminishing scars and associated symptoms.

National report - Anecdotal evidence indicates that the onion extract/allantoin gel product Mederma (Merz Pharmaceuticals) might be an effective first-line therapy for diminishing scars and associated symptoms.

According to Ronald Friedman, M.D., a plastic surgeon in Plano, Texas, who uses the product with all his postsurgical patients (about 750 patients a year), Mederma is an onion extract gel. Its purposes are to inhibit fibroblast function and proliferation. It reduces scarring, has an antibacterial property and reduces inflammation - specifically, inhibiting the release of histamine, leukotrienes and prostaglandin.

"It has anti-inflammatory and antibacterial properties and reduces scar formation at the cellular level," he says.

She finds it particularly useful when scars are in the active growth stage and are red, irritated and itchy. The scar's origin can be a surgical incision or trauma, she says.

"If you got a burn on Monday, by Tuesday, you would not be ready to use Mederma," she says. "You try to use it when the top layers of skin have healed over. Typically, I do not like putting Mederma on open wounds because it is irritating and does not help at that stage."

She generally recommends that patients use it two or three times a day on the affected area. A slight film forms once it is applied, so Dr. McMichael prescribes it once a day for patients who have visible scars on their faces or other exposed skin, and more frequently if the scars are hidden. Mederma can be used under occlusion or open, she says.

Reduces redness Dr. McMichael says that the product often diminishes redness and irritation, and sometimes shrinks scars. When patients' scars do not shrink after using Mederma for three to six months, she uses Mederma instead as an adjunct scar revision treatment, along with a monthly or bimonthly steroid injections given in the office.

According to Dr. Friedman, with Mederma, scars become softer and smoother - healing that might happen even without treatment, but Mederma speeds up the process and makes it more complete.

Dr. McMichael does not think Mederma is as effective in older scars. And it does not seem to be effective when used on post-inflammatory hyperpigmentation scars of people with dark skin types.

Before using Mederma, Dr. Friedman would sometimes use nothing on the scars, or use silicone gel sheets or vitamin E.

"The primary difference is, Mederma is inexpensive - about $15 for a 20 gram tube," Dr. McMichael says.

"It is well-tolerated. I see relatively few reactions to it. Every once in a while I see someone who says it made their skin red or itchy - that might be one in 100 patients. Mederma has a high compliance rate - people are willing to use it. It works fairly well and is widely available."

She adds that the product has a "peely" process and it makes a film, which some patients do not like. Other-wise, she says, it is a useful product with minimal side effects.

Other OTC options Store shelves are full of other types of products, but one of the problems with having so many, according to Dr. McMichael, is that while many work if used correctly, patients don't usually know the differences between over-the-counter options.

"Probably the closest things to Mederma would be the silicone agents that are coated and act as occlusive dressings," she says. "No one is sure why or how Mederma works. What we think is that not only the onion skin extract works, but also the occlusion. It seems that when you occlude a new or early scar that you have a good outcome as far as shrinking that scar."

Both doctors prescribe silicone-coated gel sheeting, but not often.

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