Treating Warts

Most of us would try anything to get rid of an unsightly wart, from treatments of –196°C liquid nitrogen to daily applications of salicylic acid for weeks on end. These mostly benign growths, caused by the human papilloma virus, often will disappear on their own within two years. That can be a long time to wait. So is it better to use the over-the-counter drops or to visit the doctor to have that pesky wart frozen off? Or is something more radical necessary?

In a recent review, researchers compared 50 studies and evaluated the effectiveness of various wart treatments. Most of the studies lacked high quality results because of poor research methods. It’s hard to compare warts because there are several types, each responding differently to treatment. Nevertheless, the researchers found the best results came from studies involving salicylic acid. This treatment involves repeatedly applying the acid directly to the wart. A number of studies involving salicylic acid showed 75% of the warts disappeared after treatment with the acid, compared to 48% of the warts treated with a placebo. Salicylic acid can be purchased over-the-counter.

Cryotherapy, in which a physician uses liquid nitrogen to freeze and kill off the wart, is the method many people turn to when salicylic acid has failed. The review found this treatment was just as effective as salicylic acid in two studies. But in two smaller trials, cryotherapy was no better than a placebo at healing the warts.

Dinitrochlorobenzene (DNCB), like salicylic acid, is applied directly to the wart. Studies showed this method was effective with a cure rate of 80% compared to 38% for placebo. But DNCB must be used much more cautiously than salicylic acid; the chemical is a known mutagen, able to cause genetic mutations. So a physician must administer DNCB. This drug induces an allergic immune response resulting in inflammation that wards off the wart-causing virus.

Other treatment options, from injections of the anti-tumor drug bleomycin to laser therapy, don’t appear to have consistent effectiveness.

Better studies are necessary to find which method of wart removal is definitively the most effective. Until then, the results of this review tell us the first plan of attack for eliminating a wart should be over-the-counter treatments with salicylic acid. If that fails, a visit to the doctor may be in order for treatment with one of the other options. In the end, though, patience might be required to allow the wart to disappear on its own.

British Medical Journal, August 31,2002

March 2003 update

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