Plantar wart treatment options equally effective

Cryotherapy and salicylic acid had similar, and low, rates of success in treating plantar warts, a new study found.

The trial included 240 patients aged 12 and over seen by a health care professional in the United Kingdom for treatment of a plantar wart. They were randomized to receive either cryotherapy with liquid nitrogen by a clinician, up to four treatments two or three weeks apart, or self-treatment with 50% salicylic acid daily for a maximum of eight weeks. The primary outcome was complete clearance of the warts at 12 weeks, but the study also looked at clearance at six months according to patient report. The results were published online by BMJ on June 7.

The study found similar rates of clearance at 12 weeks in the two groups (17/119 or 14% for salicylic acid vs. 15/110 or 14% for cryotherapy, difference 0.65%, 95% CI –8.33 to 9.63). The results did not change when adjusted for age, previous treatment and type of wart. At six months, patients reported similar rates of clearance (31% for salicylic acid vs. 34% for cryotherapy, difference –3.15%, 95% CI –16.31 to 10.02). The study also found no difference between groups in time to clearance or the number of warts at 12 weeks.

Study authors concluded that the odds of clearance appear to be similar with either treatment. They noted that cryotherapy is associated with higher cost, so that salicylic acid might be preferable. However, the study used a higher strength of salicylic acid than is typical in front-line treatment for warts, so cryotherapy might be superior to lower concentrations of the acid, the authors said. The study also found a much lower overall cure rate than most previous research, perhaps because it included patients with more resistant types of warts and those who had already tried self-treatment, the researchers speculated.

Given the low cure rates found in this study, patients may have done just as well without any intervention, concluded the authors of an accompanying editorial. Around two-thirds of warts clear within two years without treatment, the editorialists said. They suggested that future research must look for treatments that are safe, painless and do not increase morbidity, as well as investigating the possibility that HPV-subtype-specific treatment will be more effective than current strategies.