Research has shown no evidence of a difference in clearance rates between patient self-treatment and treatment given by healthcare professional for verrucae. The project was funded by the National Institute for Health Research Health Technology Assessment (NIHR HTA).
Verrucae (a type of wart) are a common, infectious and sometimes painful problem. It has been estimated that almost two million people per year see their GP about treating their warts at a cost of at least £40 million per annum. Although most verrucae will spontaneously disappear without treatment many patients seek treatment to remove a verruca due to it being painful or because they are being prevented from doing sports.
Researchers led by Sarah Cockayne of the University of York compared the clinical and cost-effectiveness of cryotherapy using liquid nitrogen given by a healthcare professional (a freezing method considered to be a more painful treatment) versus salicylic acid applied by the patient for the treatment of verrucae.
Mrs Cockayne commented; "There are many different methods of treating verruca but very little good quality research has been done to determine what is the best form of treatment. There is some evidence to suggest that salicylic acid is effective and safe but there is no clear evidence that cryotherapy is more effective than treatment with salicylic acid. "
A total of 240 participants were recruited to the trial with 117 patients allocated to receive cryotherapy given by a healthcare professional and 123 patients to self-treatment with salicylic acid. Participants were recruited from fourteen sites in England, Scotland and Ireland.
The first cryotherapy treatment was a gentle freeze lasting ten seconds with subsequent treatments undertaken according to the site's usual practice. Debridement, masking and padding of the site were also undertaken according to the site's usual practice. Participants randomised to self-treatment with salicylic acid were instructed to apply it once daily for a maximum of eight weeks.
Results showed that there was no evidence of a difference in clearance rates of verrucae between the groups at 12 weeks and at six months after enrolling into the study. Cryotherapy was also associated with higher mean costs per additional healed patient compared to salicylic acid.
The results of the study did not change when the analysis was repeated but controlled for age, whether or not the verrucae had been previously treated and type of verrucae or patients' preferences. However, the results are only applicable to verrucae or plantar warts and not warts at other sites, such as the hands, which may respond differently to cryotherapy.
Mrs Cockayne added; "We were motivated to conduct this trial when the Cochrane systematic review into the treatment of cutaneous warts highlighted the lack of good quality evidence to support the use of cryotherapy over simple topical treatments. Healthcare professionals will need to write patient information sheets in such a way to give patients realistic expectations in relation to the effectiveness of cryotherapy treatment."