Duct Tape Fails Wart-Removal Test

MINNEAPOLIS, March 20 -- In household lore, duct tape has a million uses, but it hasn't earned its way into the medicine cabinet yet, at least not as a cure for common warts.

That's the conclusion of what researchers here describe as the first double-blind controlled trial evaluating duct tape as a cure for verrucae vulgaris, or common warts, in adults.

In the study, 90 adult volunteers with at least one wart measuring from 2 mm to 15 mm were randomized to get either pads consisting of moleskin with transparent duct tape or moleskin alone, according to Rachel Wenner, M.D., of the University of Minnesota.

The volunteers were told to wear the pads for seven days and leave them off on the seventh evening. The process was repeated for two months or until the wart was cured, whichever came first, Dr. Wenner and colleagues reported in the March issue of Archives of Dermatology.

The primary endpoint was complete resolution of the wart, Dr. Wenner and colleagues reported, but there was no significant difference between the two treatment arms at the end of two months.

The researchers found that, among the 80 volunteers who completed the study, eight of the 39 in the treatment group (or 21%) had complete resolution, compared with nine of the 41 in the control arm (or 22%).

"During the treatment period, the mean diameter and height of the target wart decreased regardless of study group assignment," the researchers said. Differences between the arms in height and diameter were less than 0.4 mm on average and were not significantly different.

In a logistic regression analysis, the only factor significantly associated (at P=0.006) with the likelihood of complete resolution was the duration of the wart - newer warts were more likely to resolve than established lesions, Dr. Wenner and colleagues found.

The finding contradicts one earlier study: In a small trial in children, reported in Archives of Pediatrics & Adolescent Medicine in 2002, duct tape appeared to outperform cryotherapy. But that trial was criticized because the blinding was unlikely to have been completely effective, the researchers said.

On the other hand, a 2006 study in the same journal reported that duct tape was no better than placebo, although that study was not double-blinded. (Sticky Duct Tape Fails as Wart Treatment in School Children)

Several mechanisms have been suggested for the purported benefit of duct tape, but the current study suggests that occlusion of the wart is not the therapeutic mechanism, if there is one, the researcher said.

One possibility is an effect of the adhesive in the tape. For this study, the researchers said, transparent duct tape was used to preserve the blinding, after information from the manufacturers said it contained the same rubber-based adhesive as the standard silver tape.

Later, however, the manufacturer said that in fact the adhesive was acrylic- based, like that used in the moleskin. "It is possible that the rubber-based adhesive or other components of an adhesive not found on our study tape are required for effective treatment of warts," the researchers said.