Cryotherapy plus oral zinc sulfate versus cryotherapy plus placebo to treat common warts: A double blind, randomized, placebo-controlled trial

Background: Cutaneous warts are caused by a small group of specific types of human papillomaviruses. Cryotherapy is a highly effective treatment for patients with viral warts; however, it is a painful method and usually requires several treatment sessions. Zinc is a trace element with many proven effects on the immune system. Objective: Our aim was to assess the efficacy and safety of oral zinc sulfate in the treatment and recurrence rate of common warts. Methods: Eighty-three patients with common warts participated in this double-blind, randomized, placebo-controlled trial. In both groups, three sessions of liquid nitrogen cryotherapy were performed for up to 2 months with 3-week intervals. The treatment group (n = 45) received oral zinc sulfate capsules in a dose of 10 mg/kg per day up to 600 mg day. The control group (n = 38) was provided with placebo of similar appearance. Treatment continued for 2 months and the follow-up period lasted up to 6 months. Results: Warts completely resolved in 26 patients in the treatment group (68.4%) and 23 patients in the placebo group (63.9%; p = .68). Three patients (7.9%) in the treatment group and six patients (16.6%) in the placebo group has a recurrence of the warts (p = .19). Conclusion: According to our study, the addition of zinc to cryotherapy was not beneficial in the treatment of patients with common warts nor did it prevent recurrences