Cryotherapy of 2 weeks versus 3 weeks interval for Common warts


Background and objective: Cryotherapy with liquid nitrogen is a widely used method for treatment of common warts by dermatologists. Traditionally, when treating warts, liquid nitrogen is applied at intervals of 3 weeks. This study was designed to compare the efficacy, and time to clearance of 2-week and 3-week interval cryotherapy of patients attending the department of dermatology and venereology at Rizgary Teaching Hospital in Erbil City.Methods: In This comparative study 80 immunocompetant patients, age range 10-55 years with common warts on the hands and/or feet were enrolled from November 2008 through May 2009. Patients were randomized to receive cryotherapy at interval of either 2 or 3 weeks. All patients allocated to have liquid nitrogen applied with a cryo-spray technique. Cure rates were evaluated in both groups after 3 months and after 6 treatments.Results: 72 patients completed the study. The mean times for clearance of all warts in both groups were 9 weeks in every 2-week treatment group and 14 weeks in every 3-week treatment group. The mean numbers of treatment sessions required to achieve clearance were similar in each group (4.5 and 4.7 treatment sessions) for 2- and 3- week interval groups respectively. Cure rates at 3 months were 64% in the 2-week interval treatment group and 45% in the 3-week group. After 6 treatment sessions cure rates were similar for both groups; 65% and 60% for 2- and 3- week interval groups respectively. Morbidity was slightly greater in the 2-week interval treatment group.Conclusion: Cryotherapy of common warts is effective and the percentage of cure is related to the number of treatments received, and independent from the period between treatments.