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New Treatments for Warts Show Promise

Posted - Jul. 1, 2003 at 6:40 a.m.



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The Seattle Times

(KRT)

SEATTLE - Few things fit their name so wonderfully as the wart.

The word is squat and ugly, like the object it represents.

It does not have an ominous ring to it, but it sounds pesky and persistent - like something sticky on the bottom of your shoe.

That's why last fall's news that duct tape might be an effective treatment for warts seemed so perfect. Could a humble household staple banish an annoying, but humdrum, human affliction?

Dermatologists, who have seen other wart breakthroughs fizzle, were wary.

"There are people who say spells over their warts, or bury potatoes in the back yard to get rid of them, but that doesn't mean it works," said Dr. Robert Brodell, author of the first new book in years on the diagnosis and treatment of warts.

"It turns out warts are very difficult to treat."

Duct tape may work in some cases, but it's not likely to revolutionize the field, said Brodell, a professor of medicine at Northeastern Ohio Universities College of Medicine.

More promising are several new prescription treatments, including interferon cream, yeast shots and a popular ulcer pill, that switch on the body's own immune system to fight the virus responsible for warts. It's possible that ongoing research could even lead to development of a vaccine against warts, he said.

There's also a new over-the-counter alternative: A do-it-yourself wart-freezing kit.

"The good news is that we now have a wide variety of different (treatments) to use," Brodell said. "If they're tailored for each patient, it's a rare person we can't help get better."

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Warts are caused by a viral infection in the top layer of skin. The virus hijacks the skin cells' reproductive machinery, causing them to proliferate and form bumps.

Common warts are usually hard and rough on top, but they also can be fleshy and soft.

The hands are prime territory, along with feet, eyelids and elbows.

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There are three main types of warts, all caused by strains of human papillomavirus:

Common warts: Usually hard and rough, they most often grow on hands. They are sometimes called "seed" warts, because blood vessels in the wart look like dark seeds.

Frond-like filiform warts grow on eyelids, necks or lips.

Plantar warts: Grow on the soles (plantar surface) of feet. Clusters are called mosaic warts. Hard to treat because pressure from walking drives the virus deep into the foot.

Flat warts: Smaller and smoother than other warts, they tend to grow in large numbers, particularly on the face and legs.

Warts seem to be most prevalent in children, though they are also abundant among adults.

"Millions of people have common warts," said Brodell. "There would never be a day in my private practice when I didn't see multiple patients being treated for warts."

In addition to paying for all those office visits - most of which are covered by insurance - Americans spend $65 million a year on over-the-counter wart remedies.

And that does not take into account people who turn to folk remedies, like rubbing warts with a piece of potato, then burying the spud in the yard. Other favored rituals involve cutting off a rooster's comb, tying a piece of thread around the wart or tossing a bone after rubbing it on the blemish.

Why so much effort to get rid of something that's essentially harmless?

"I just prefer having smooth skin," said Bruce Haley, a Seattle software designer.

As a kid, Haley recalls whittling away a wart with his Swiss Army knife. "I chopped all the way down to the root and got rid of it," he said. "It was a pretty bloody operation."

When he heard about the duct tape method, he decided to try it on a wart on the palm of his hand.

The shiny gray tape was long-rumored to be an effective weapon against warts, but researchers at Madigan Army Medical Center in Tacoma, Wash., were the first to test the notion scientifically. One group of patients had their warts frozen with liquid nitrogen. The others followed a regimen that involved covering the wart with duct tape for six days, soaking and scraping the wart, then replacing the tape.

The duct tape method outperformed freezing, the standard doctor's office treatment.

Haley's results were not so impressive.

He taped his wart for at least two months, camouflaging the site with flesh-colored medical tape when people started to notice.

"When I finally decided to stop, the wart was still there."

That sums up the problem with wart treatments, said Dan Berg, head of dermatological surgery at the University of Washington Medical Center. "There are no magic bullets. There's nothing that's cheap, easy and painless that works on all of them."

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Warts are flesh-colored and usually rough. Moles are smooth and vary from pink to black.

Still, dermatologists generally recommend against a laissez faire approach.

Though they do not spread easily, warts are contagious and often pass between family members. In at least 30 percent of cases, they go away on their own. But if they don't, they can grow, sprout other warts and become painful, especially on the soles of feet.

Wart viruses are in the same family as the human papillomaviruses that cause genital warts, a more serious, sexually transmitted condition that can lead to cervical and penile cancer.

Though it's exceedingly rare for a common wart to become cancerous, common warts can spread to the genital area, Brodell said.

"In my opinion, all warts should be treated."

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Traditional wart treatments, such as over-the-counter remedies and freezing, are based on a simple approach: Remove the wart and hope it does not come back. They do not always work, because it is hard to get rid of all infected tissue.

"There's always a little virus left in the skin, that you can't see with the naked eye," Brodell said.

The newest treatments aim to attack the wart viruses directly, by boosting the body's immune response.

In addition to reducing stomach acid, high doses of the prescription ulcer drug Tagamet can activate the immune-system cells that are key to fighting wart viruses. A few small studies suggest it may be helpful for children, but its usefulness in adults remains unclear.

Even more promising is a cream called imiquimod, which stimulates production of the infection-fighting substance interferon. In some studies, most patients saw their warts either shrink or vanish. In another experiment, the cream seemed to work best in combination with freezing or other conventional treatment.

Many dermatologists are especially optimistic about yeast shots.

Candin, an extract of a common yeast that lives on the skin, seems to stimulate the body's wart-fighting machinery when injected directly into warts. And even more intriguing, the treatment may banish all warts - not just the injected one.

According to a study presented in March at an American Academy of Dermatology conference, uninjected warts also disappeared in nearly half of patients who got the treatment.

Kirkland dermatologist Dr. Joanna Sloan attended the conference and tried the yeast injections on a few patients, including one with more than 100 warts.

"That's kind of mission impossible with most treatments," said Sloan, who is still waiting to see if the shots work.

A vaccine would be the ultimate anti-wart shot.

There are already vaccines to prevent warts in cows and beagles - the latter because dogs infected with wart viruses cannot be used in medical research. Researchers at the University of Washington have developed a vaccine for the closely related virus that causes some cases of cervical cancer. It should be possible to extend those successes to the common wart, if it proves economically worthwhile, experts say.

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Until the new methods are better established, standard treatments remain the mainstay in the war on warts.

Over-the-counter products, such as Compound W, use salicylic acid to kill the tissue. Applied as a liquid, as a gel or in pads, they can take up to 12 weeks to eradicate a wart. Cure rates range up to 75 percent.

They work best on small warts, said Seattle dermatologist Dr. Brandith Irwin.

"If you have a big, thick wart on the bottom of your foot, I wouldn't waste your time with over-the-counter treatments," she said.

New to the American market is Wartner, the first method that allows people to freeze their own warts. A small canister that sells for $19.99, Wartner contains a mixture of pressurized gases that form a foam that chills warts to minus 70 degrees Fahrenheit.

The most popular treatment in France and Switzerland, Wartner can eliminate many warts with a single freezing, said marketing director Steve Bosking.

Sloan, the Kirkland dermatologist, is skeptical. It's probably fine for smaller warts, but can't match the minus-320-degree freezing power of liquid nitrogen, which dermatologists use, she said. Even with liquid nitrogen, it usually takes at least three treatments to destroy a wart, including its "root," the infected tissue below the surface. Big warts on the bottom of the feet, called plantar warts, can require six freezings.

"Warts are kind of like icebergs," she said. "There is a lot underneath."

Freezing warts can be painful, so for children dermatologists often use an extract from blister beetles called cantharidin - also known as Spanish fly, a purported aphrodisiac. The wart blisters and peels away in layers.

For the most stubborn warts, dermatologists inject a chemotherapy agent called bleomycin, a costly treatment that kills the tissue and turns it black. And there's always the alternative of cutting the wart away or blasting it with a laser, both of which are considered last-ditch alternatives.

"If you excise a wart on somebody's heel, they'll be on crutches for a week or two," Sloan said.

Despite technological advances, some people prefer low-tech approaches, swearing by hypnosis or visualization.

There's a chance that mental images of a shriveling wart could activate the immune system, Brodell said. But he suspects any success is more likely due to luck.

"Some warts will go away anyway, no matter what you do."

And if they don't, there's always that roll of duct tape in the drawer.

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How to avoid warts and keep them from spreading

-Wash your hands often, particularly after being around people with warts.

-Wear shower shoes around swimming pools and in public showers.

-Don't use the same nail clippers or fingernail file on warts as on healthy nails (warts are common along the edge of the nail bed).

-Avoid picking at warts, which can spread the virus.

(C) 2003 Knight Ridder/Tribune News Service.. All Rights Reserved

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