Clinical, histopathologic, and viral load study after treatment of plantar warts with 10% formaldehyde soaks versus liquid nitrogen cryotherapy

Background Although various therapies are available, warts often present a difficult treatment problem for clinicians because of the lack of specific antipapillomavirus agents. Plantar warts, in particular, are types of viral warts that are notoriously difficult to treat. Objective To compare the clinical, histopathologic, and viral load changes following treatment of multiple plantar warts using formaldehyde soaks versus liquid nitrogen cryotherapy. Patients and methods The study included 28 patients with multiple plantar warts, randomized into two treatment groups: group I (13 patients) and group II (15 patients) that received topical 10% formaldehyde soaks twice daily and cryotherapy every 2 weeks, respectively. Treatment continued for up to 3 months (study end point). The patients were followed up for 3 months after treatment and evaluated clinically, histopathologically, and by insitu hybridization. Results Both treatments resulted in almost similar clinical outcome with clearance of warts in 46.2 and 46.7% of patients in group I and group II, respectively. Moreover, both treatments resulted in a statistically significant decrease of human papilloma virus-DNA positive cells, with no statistically significant difference between the two groups. Conclusion The results suggested that treatment of multiple plantar warts using either formaldehyde soaks or liquid nitrogen cryotherapy yields almost similar cure rates as well as similar reduction in human papilloma virus-DNA viral load. However, as formaldehyde soaks are equally effective and less costly, with no need for multible visits for clinic, their use may be favoured over cryoherapy as a treatment for multiple and extensive plantar warts. However, further researches should focus on the study of its safety and efficacy in a larger number of patients to support these findings.