BehindTheMedspeak: Duct tape and warts — time for a reassessment?

Much excitement accompanied a 2002 report confirming the old wives' tale that duct tape is a highly effective wart removal remedy.

But a study published in November, 2006 in the Archives of Pediatrics & Adolescent Medicine, with about twice the number of subjects studied in the 2002 report, found that duct tape isn't any better than corn pads.

This comes on top of last year's meta-study, which compiled and analyzed data from 60 reports on a wide variety of removal techniques and concluded that simple salicylic acid skin soaks were the best, with a 73% cure rate.

All this, and more, was contained in Anahad O'Connor's February 27, 2007 New York Times Science section "Really?" feature, which follows.

The Claim: Duct Tape Removes Warts

The Facts: A small study in 2002 gave credence to an old remedy for an ugly problem when it stated that duct tape, that ever-popular emblem of inventiveness and quick fixes, was a highly effective treatment for warts.

The practice is supposed to work because the tape, if left on long enough, irritates the skin, thereby causing an immune reaction that clears up the infections responsible for warts, which are most common in children. The 2002 study found that if applied for six days, duct tape worked more often than the usual technique: cryotherapy, or freezing.

But many critics questioned the size of the study and its methodology, and this month they gained ammunition from a study that appeared in The Journal of Family Practice. [It was originally published in November, 2006 in the Archives of Pediatrics & Adolescent Medicine.]

In the study, tape was applied to problem areas for seven days and then the spots were soaked in warm water and rubbed with pumice stones. This technique worked about 16 percent of the time, about the same as applying corn pads overnight with once-weekly soaks and rubs. The researchers looked at 103 children — twice the number of subjects in the 2002 study.

Last year, another study went a step further by compiling and analyzing data from 60 studies that had looked at various removal methods. That study, published in the Cochrane Database of Systematic Reviews, found that simple skin treatments with salicylic acid were probably the best option. Applied regularly, the study found, they had a cure rate of about 73 percent.

The Bottom Line: Duct tape may not be as effective as once thought.

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Here's a link to the abstract of the 2002 article in the Archives of Pediatrics & Adolescent Medicine that found duct tape to be effective; the abstract itself follows.

The Efficacy of Duct Tape vs Cryotherapy in the Treatment of Verruca Vulgaris (the Common Wart)

Objective: To determine if application of duct tape is as effective as cryotherapy in the treatment of common warts.

Design: A prospective, randomized controlled trial with 2 treatment arms for warts in children.

Setting: The general pediatric and adolescent clinics at a military medical center.

Patients: A total of 61 patients (age range, 3-22 years) were enrolled in the study from October 31, 2000, to July 25, 2001; 51 patients completed the study and were available for analysis.

Intervention: Patients were randomized using computer-generated codes to receive either cryotherapy (liquid nitrogen applied to each wart for 10 seconds every 2-3 weeks) for a maximum of 6 treatments or duct tape occlusion (applied directly to the wart) for a maximum of 2 months. Patients had their warts measured at baseline and with return visits.

Main Outcome Measure: Complete resolution of the wart being studied.

Results: Of the 51 patients completing the study, 26 (51%) were treated with duct tape, and 25 (49%) were treated with cryotherapy. Twenty-two patients (85%) in the duct tape arm vs 15 patients (60%) enrolled in the cryotherapy arm had complete resolution of their warts (P = .05 by {chi}2 analysis). The majority of warts that responded to either therapy did so within the first month of treatment.

Conclusion: Duct tape occlusion therapy was significantly more effective than cryotherapy for treatment of the common wart.

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That was fun, eh?

Next, the abstract of the November, 2006 paper in the same journal that refuted the 2002 study.

Efficacy of Duct Tape vs Placebo in the Treatment of Verruca Vulgaris (Warts) in Primary School Children

Objective: To determine the efficacy of duct tape compared with placebo in the treatment of verruca vulgaris.

Design and Setting: A randomized placebo-controlled trial in 3 primary schools in Maastricht, the Netherlands.

Participants: One hundred three children aged 4 to 12 years with verruca vulgaris.

Interventions: Duct tape applied to the wart or placebo, a corn pad (protection ring for clavi), applied around the wart for 1 night a week. Both treatments were applied for a period of 6 weeks. Patients were blinded to the hypothesis of the study.

Main Outcome Measurement: Complete resolution of the treated wart.

Results: After 6 weeks, the wart had disappeared in 16% of the children in the duct tape group compared with 6% in the placebo group (P = .12). The estimated effect of duct tape compared with placebo on diameter reduction of the treated wart was 1.0 mm (P = .02, 95% confidence interval, –1.7 to –0.1). After 6 weeks, in 7 children (21%) in the duct tape group, a surrounding wart had disappeared compared with 9 children (27%) in the placebo group (P = .79). Fifteen percent of the children in the duct tape group reported adverse effects such as erythema, eczema, and wounds compared with 0 in the placebo group (P = .14).

Conclusion: In a 6-week trial, duct tape had a modest but nonsignificant effect on wart resolution and diameter reduction when compared with placebo in a cohort of primary school children.

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Last but not least, the abstract of last year's Cochrane Database Meta-study.

Topical Treatments for Cutaneous Warts

Background: Viral warts are common and usually harmless but very troublesome. A very wide range of local treatments are used.

Objectives: To assess the effects of different local treatments for cutaneous, non-genital warts in healthy people.

Search strategy: We searched the Cochrane Skin Group Specialised Register (March 2005), the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 1, 2005), MEDLINE (1966 to March 2005), EMBASE (1980 to March 2005) and a number of other biomedical databases. The references of all trials and selected review articles were also searched. In addition, we contacted pharmaceutical companies involved in local treatments for warts and experts in the field

Selection criteria: Randomised controlled trials of local treatments for cutaneous non-genital viral warts in immunocompetent (healthy) people.

Data collection and analysis: Data was extracted and two authors independently selected the trials and assessed methodological quality.

Main results: Sixty trials were identified that fulfilled the criteria for inclusion. The evidence provided by these studies was generally weak due to poor methodology and reporting.

In 21 trials with placebo groups that used participants as the unit of analysis, the average cure rate of placebo preparations was 27% (range 0 to 73%) after an average period of 15 weeks (range 4 to 24 weeks).

The best available evidence was for simple topical treatments containing salicylic acid, which were clearly better than placebo. Data pooled from five placebo-controlled trials showed a cure rate of 117/160 (73%) compared with 78/162 (48%) in controls, which translates to a risk ratio of 1.60 (95% confidence interval 1.16 to 2.23), using a random effects model.

Evidence for the absolute efficacy of cryotherapy was surprisingly lacking. Two trials comparing cryotherapy with salicylic acid and one comparing duct tape with cryotherapy showed no significant difference in efficacy.

Evidence for the efficacy of the remaining treatments reviewed was limited.

Authors' conclusions: There is a considerable lack of evidence on which to base the rational use of topical treatments for common warts. The reviewed trials are highly variable in method and quality. Cure rates with placebo preparations are variable but nevertheless considerable. There is certainly evidence that simple topical treatments containing salicylic acid have a therapeutic effect. There is less evidence for the efficacy of cryotherapy, but reasonable evidence that it is only of equivalent efficacy to simpler and safer treatments. The benefits and risks of topical dinitrochlorobenzene and 5-fluorouracil, intralesional bleomycin and interferons, photodynamic therapy and other miscellaneous treatments remain to be determined.

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You want my bottom line?

Okay.

You really have much better things to do than spend this much time investigating wart remedies.

But I digress.

I doubt you've got corn pads or salicylic acid in your place but I'd put much higher odds on the chance there's a roll of duct tape around somewhere.

And one of my cardinal rules of medicine is that if something is harmless, then even if it may be less effective than something else, it's worth a shot.

So me, I'd go with a few rounds of duct tape before bringing out the heavy artillery and my wallet at Walgreen's.