Cryotherapy May Be Most Effective for Removal of Common Warts

Canadian Medical Association Journal, September 13 2010 (Published online)

A randomized controlled trial that compared the effectiveness of common wart treatments (Liq Nitrogen Vs Salicylic Acid) as well as a wait-and-see approach.

Introduction:

"Cryotherapy is widely used for the treatment of cutaneous warts in primary care"
"However, evidence favours salicylic acid application"

Method:

Between May 1, 2006, and January 26, 2007, all eligible patients with new cutaneous warts were recruited from 30 primary care practices in the Netherlands and were randomly assigned to 1 of 3 groups: cryotherapy with liquid nitrogen every 2 weeks, daily self-application of salicylic acid, or a wait-and-see approach.

The proportion of participants with cure of all warts at 13 weeks was the main study endpoint, and analysis was by intent-to-treat. Treatment adherence, adverse effects, and satisfaction with treatment were secondary endpoints. At 4, 13, and 26 weeks, research nurses evaluated outcomes during home visits.

Results:

Of the 250 participants, 122 (49%) were stratified into the common wart group and 128 (51%) into the plantar wart group.

Age range of the participants was 4 to 79 years.

At 13 weeks, 10 patients (4%) were lost to follow-up, and 240 were included in the analysis.

In the cryotherapy group, cure rate was 39(95% confidence interval [CI], 29% - 51%) vs 24% (95% CI, 16% - 35%) in the salicylic acid group and 16% (95% CI, 9.5% - 25%) in the wait-and-see group.

For participants with common warts (n = 116), these differences in efficacy were most pronounced. Cure rates were 49% with cryotherapy (95% CI, 34% - 64%), 15% with salicylic acid (95% CI, 7% - 30%), and 8% with the wait-and-see approach. The different treatments were not associated with significant differences in cure rates among participants with plantar warts (n = 124).

Limitation:

Limitations of this study include self-application of salicylic acid and lack of blinding of participants, family practices, and research nurses.

Conclusion:

"Although earlier evidence favoured salicylic acid application above cryotherapy, the present randomized controlled trial is the first that provides evidence to support the use of cryotherapy above salicylic acid, however, for common warts only,"