Treatment of verrucae vulgares in general practice — a randomized controlled trial on the effectiveness of liquid nitrogen and the Histofreezer

Efficacy and Safety of Three Cryotherapy Devices for Wart Treatment: A Randomized, Controlled, Investigator-Blinded, Comparative Study

INTRODUCTION

Cutaneous warts are common skin lesions, caused by human papillomavirus. For years, liquid nitrogen is the cryogen of choice for wart treatment. Alternatively, several cryogenic devices for home treatment are commercially available. The present trial assessed efficacy and safety of a novel nitrous oxide-based cryogenic device for home use (EndWarts Freeze® in Europe, Compound W® Nitro-Freeze in the USA).

METHODS

This investigator-blinded, controlled, randomized study compared the nitrous oxide device (test product) with a dimethylether propane-based product (Wartner®; comparator 1). Subjects with common or plantar warts (50/50 ratio) were randomized into two groups (n = 58, test product; n = 40, comparator 1). Sequentially, an extra treatment arm (n = 40) was added to compare with a dimethylether-based product with metal nib (Wortie®; comparator 2). Main objective implied comparison of the percentage cured subjects after one to maximum three treatments. Efficacy and safety was evaluated by a blinded investigator.

RESULTS

After a maximum of three applications, a significantly (p = 0.001) higher cure rate of 70.7% (Intention-to-Treat analysis) was observed with test product versus 46.2% (comparator 1) and 47.5% (comparator 2). Almost three times more subjects were cured after 1 test product application (29.3%), versus comparator 1 (10.4%) and comparator 2 (12.5%). Reported side effects were transient and typical of cryotherapy. All treatments were well-tolerated.

CONCLUSION

The superior cure rates for the test product versus two comparators can be explained by its design. Combination of nitrous oxide (cooling agent), the specific activation method (holding the liquid coolant in the cap), and skin-conforming polyurethane foam, results in higher cooling efficiency (- 80 °C) and more effective wart freezing. This trial demonstrated that the nitrous oxide device is a safe, user-friendly and effective wart treatment for home use, comparing favourably to dimethylether (propane) devices with higher freezing temperature, regardless of the applicator type.

FUNDING

Oystershell Laboratories.

TRIAL REGISTRATION

Clinicaltrials.gov identifier, NCT03129373.

Topical treatments for cutaneous warts

BACKGROUND

Viral warts are a common skin condition, which can range in severity from a minor nuisance that resolve spontaneously to a troublesome, chronic condition. Many different topical treatments are available.

OBJECTIVES

To evaluate the efficacy of local treatments for cutaneous non-genital warts in healthy, immunocompetent adults and children.

SEARCH METHODS

We updated our searches of the following databases to May 2011: the Cochrane Skin Group Specialised Register, CENTRAL in The Cochrane Library, MEDLINE (from 2005), EMBASE (from 2010), AMED (from 1985), LILACS (from 1982), and CINAHL (from 1981). We searched reference lists of articles and online trials registries for ongoing trials.

SELECTION CRITERIA

Randomised controlled trials (RCTs) of topical treatments for cutaneous non-genital warts.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials and extracted data; a third author resolved any disagreements.

MAIN RESULTS

We included 85 trials involving a total of 8815 randomised participants (26 new studies were included in this update). There was a wide range of different treatments and a variety of trial designs. Many of the studies were judged to be at high risk of bias in one or more areas of trial design.Trials of salicylic acid (SA) versus placebo showed that the former significantly increased the chance of clearance of warts at all sites (RR (risk ratio) 1.56, 95% CI (confidence interval) 1.20 to 2.03). Subgroup analysis for different sites, hands (RR 2.67, 95% CI 1.43 to 5.01) and feet (RR 1.29, 95% CI 1.07 to 1.55), suggested it might be more effective for hands than feet.A meta-analysis of cryotherapy versus placebo for warts at all sites favoured neither intervention nor control (RR 1.45, 95% CI 0.65 to 3.23). Subgroup analysis for different sites, hands (RR 2.63, 95% CI 0.43 to 15.94) and feet (RR 0.90, 95% CI 0.26 to 3.07), again suggested better outcomes for hands than feet. One trial showed cryotherapy to be better than both placebo and SA, but only for hand warts.There was no significant difference in cure rates between cryotherapy at 2-, 3-, and 4-weekly intervals.Aggressive cryotherapy appeared more effective than gentle cryotherapy (RR 1.90, 95% CI 1.15 to 3.15), but with increased adverse effects.Meta-analysis did not demonstrate a significant difference in effectiveness between cryotherapy and SA at all sites (RR 1.23, 95% CI 0.88 to 1.71) or in subgroup analyses for hands and feet.Two trials with 328 participants showed that SA and cryotherapy combined appeared more effective than SA alone (RR 1.24, 95% CI 1.07 to 1.43).The benefit of intralesional bleomycin remains uncertain as the evidence was inconsistent. The most informative trial with 31 participants showed no significant difference in cure rate between bleomycin and saline injections (RR 1.28, 95% CI 0.92 to 1.78).Dinitrochlorobenzene was more than twice as effective as placebo in 2 trials with 80 participants (RR 2.12, 95% CI 1.38 to 3.26).Two trials of clear duct tape with 193 participants demonstrated no advantage over placebo (RR 1.43, 95% CI 0.51 to 4.05).We could not combine data from trials of the following treatments: intralesional 5-fluorouracil, topical zinc, silver nitrate (which demonstrated possible beneficial effects), topical 5-fluorouracil, pulsed dye laser, photodynamic therapy, 80% phenol, 5% imiquimod cream, intralesional antigen, and topical alpha-lactalbumin-oleic acid (which showed no advantage over placebo).We did not identify any RCTs that evaluated surgery (curettage, excision), formaldehyde, podophyllotoxin, cantharidin, diphencyprone, or squaric acid dibutylester.

AUTHORS' CONCLUSIONS

Data from two new trials comparing SA and cryotherapy have allowed a better appraisal of their effectiveness. The evidence remains more consistent for SA, but only shows a modest therapeutic effect. Overall, trials comparing cryotherapy with placebo showed no significant difference in effectiveness, but the same was also true for trials comparing cryotherapy with SA. Only one trial showed cryotherapy to be better than both SA and placebo, and this was only for hand warts. Adverse effects, such as pain, blistering, and scarring, were not consistently reported but are probably more common with cryotherapy.None of the other reviewed treatments appeared safer or more effective than SA and cryotherapy. Two trials of clear duct tape demonstrated no advantage over placebo. Dinitrochlorobenzene (and possibly other similar contact sensitisers) may be useful for the treatment of refractory warts.

Treatment of cutaneous warts: an evidence-based review

Cutaneous warts are common skin lesions caused by human papillomavirus infection. Treatment is aimed at relieving the patient's physical and psychological discomfort and at preventing the spread of infection by autoinoculation. Among the available medical and destructive therapeutic options for cutaneous warts, none is uniformly effective or virucidal. Moreover, in most cases their safety and efficacy has not been assessed in double-blind, controlled clinical trials, so that the reproducibility of many of the listed treatments is difficult to evaluate and a possible placebo effect cannot be ruled out. The aim of this article is to describe the outcome of current therapies for each clinical wart type according to evidence-based medicine studies published in the literature. For each clinical form, the existing treatments are classified as first-, second-, and third-line therapy. First-line therapy includes medical treatments (salicylic acid, silver nitrate, glutaraldehyde) that are useful to treat a single wart or a few and/or small common warts of short duration (less than 1 year). If these treatments have failed or are contraindicated, cryotherapy may be considered as second-line therapy. For recurrent or difficult-to-treat lesions, third-line therapy includes a variety of alternative therapeutic options (topical, intralesional, systemic, and physical destruction) that are generally off-label (not US FDA approved), and whose use is limited by drawbacks or adverse effects. From pooled evidence-based medicine data, it is possible to conclude that significantly higher remission rates may be expected only with cryotherapy and salicylic acid used in combination.

Topical zinc oxide vs. salicylic acid?lactic acid combination in the treatment of warts

BACKGROUND

Warts are a common dermatologic problem. Treatment is painful, prolonged, and can cause scarring.

OBJECTIVE

To evaluate topical zinc oxide for the treatment of warts.

METHODS

This was a randomized, double-blind controlled trial of 44 patients. Twenty-two patients were given topical zinc oxide 20% ointment, and the other 22 received salicylic acid 15% + lactic acid 15% ointment twice daily. All patients were followed up for 3 months or until cure, whichever occurred first. All patients were observed for side-effects.

RESULTS

Sixteen patients in the zinc group and 19 in the salicylic acid-lactic acid group completed the study. In the zinc oxide-treated group, 50% of the patients showed complete cure and 18.7% failed to respond, compared with 42% and 26%, respectively, in the salicylic acid-lactic acid-treated group. No patients developed serious side-effects.

CONCLUSION

Topical zinc oxide is an efficacious, painless, and safe therapeutic option for wart treatment.

To freeze or not to freeze: a cost-effectiveness analysis of wart treatment

BACKGROUND

Several general practitioner (GP)-prescribed and over-the-counter therapies for warts and verrucae are available. However, the cost-effectiveness of these treatments is unknown.

OBJECTIVES

To compare the cost-effectiveness of different treatments for cutaneous warts.

METHODS

We designed a decision-analytic Markov simulation model based on systematic review evidence to estimate the cost-effectiveness of various treatments. The outcome measures studied are percentage of patients cured, cost of treatment and incremental cost-effectiveness ratio for each treatment, compared with no treatment, after 18 weeks.

RESULTS

Duct tape was most cost-effective but published evidence of its effectiveness is sparse. Salicylic acid was the most cost-effective over-the-counter treatment commonly used. Cryotherapy administered by a GP was less cost-effective than GP-prescribed salicylic acid and less cost-effective than cryotherapy administered by a nurse.

CONCLUSIONS

Duct tape could be adopted as the primary treatment for cutaneous warts if its effectiveness is verified by further rigorous trials. Nurse-administered cryotherapy is likely to be more cost-effective than GP-administered cryotherapy.

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.

Local treatments for cutaneous warts

BACKGROUND

Viral warts caused by the human papilloma virus represent one of the most common diseases of the skin. Any area of skin can be affected although the hands and feet are by far the commonest sites. A very wide range of local treatments are available.

OBJECTIVES

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

SEARCH STRATEGY

We searched the Cochrane Controlled Trials Register (January 2003), the Skin Group trials register (January 2003), MEDLINE (1966 to January 2003), EMBASE (1980 to January 2003) and a number of other key biomedical and health economics databases. In addition the cited references of all trials identified and key review articles were searched. Pharmaceutical companies involved in local treatments for warts and experts in the field were contacted. The most recent searches were carried

SELECTION CRITERIA

Randomised controlled trials of local treatments for cutaneous non-genital viral warts in immunocompetent human hosts were included.

DATA COLLECTION AND ANALYSIS

Study selection and assessment of methodological quality were carried out by two independent reviewers.

MAIN RESULTS

Fifty two trials were identified which fulfilled the criteria for inclusion in the review. The evidence provided by these studies was generally weak because of poor methodology and reporting. In 17 trials with placebo groups that used participants as the unit of analysis the average cure rate of placebo preparations was 30% (range 0 to 73%) after an average period of 10 weeks (range 4 to 24 weeks). The best available evidence was for simple topical treatments containing salicylic acid, which are clearly better than placebo. Data pooled from six placebo-controlled trials show a cure rate of 144/191 (75%) compared with 89/185 (48%) in controls, odds ratio 3.91 (95% confidence interval 2.40 to 6.36), random effects model. Most of the bigger trials of cryotherapy studied different regimens rather than comparing cryotherapy with other treatments or placebo. Pooled data from two small trials that included cryotherapy and placebo or no treatment, showed no significant difference in cure rates. In two trials comparing cryotherapy with salicylic acid and one comparing duct tape with cryotherapy no significant difference in efficacy was demonstrated. There was no consistent evidence for the effectiveness of intralesional bleomycin. Four studies, using warts rather than individuals as the unit of analysis, had widely varying results which could not be meaningfully pooled. There was some evidence for the efficacy of dinitrochlorobenzene, a potent contact sensitizer. Pooled data from two small studies comparing dinitrochlorobenzene with placebo showed cure rates of 32/40 (80%) and 15/40 (38%) respectively, odds ratio 6.67 (95% confidence interval 2.44 to 18.23), random effects model. Only limited evidence was found for the efficacy of topical 5-fluorouracil, intralesional interferons and photodynamic therapy.Bleomycin, dinitrochlorobenzene, 5-fluorouracil, interferons and photodynamic therapy are potentially hazardous or toxic treatments.

REVIEWER'S CONCLUSIONS

There is a considerable lack of evidence on which to base the rational use of the local 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 and some evidence that it is only of equivalent efficacy to simpler, safer treatments. Dinitrochlorobenzene appears to be effective but there were no statistically significant differences when compared with the safer, simpler and cheaper topical treatments containing salicylic acid. The benefits and risks of 5-fluorouracil, bleomycin, interferons and photodynamic therapy remain to be determined.