CONCISE COMMUNICATION Effectiveness and safety profile of 40% trichloroacetic acid and cryotherapy for plantar warts Fatma Pelin CENGIZ, Nazan EMIROGLU, Ozlem SU, Nahide ONSUN Department of Dermatology, Bezmialem Vakif University Hospital, Bezmialem Vakif University, Istanbul, Turkey ABSTRACT Plantar warts are one of the most common infectious skin disease caused by the human papillomavirus. In this study, cryotherapy with liquid nitrogen delivered by the physician, up to four treatments 2 weeks apart. Forty percent tri- chloroacetic acid (TCA) was applied to warts weekly up to four treatments. At the end of 4 weeks, the clinical improvement of the TCA group (n = 30) was six patients (20%) with no change, one patient (3.3%) with a mild response, 13 patients (43.3%) with a moderate response and 10 patients (33.3%) with a good response. In the cryotherapy group, clinical responses were 12 patients (40%) with no change, four patients (13.3%) with a mild response, 12 patients (40%) with a moderate response and two patients (6.7%) with a good response. There was a statistically significant difference in improvement between the two treatment groups (P = 0.027). According to our results, TCA 40% is more effective for clearance of plantar warts with significantly improved long-term safety profile. Key words: cryotherapy, effectiveness, plantar, trichloroacetic acid, wart. INTRODUCTION Cutaneous warts, a cutaneous manifestation of the human papillomavirus (HPV), are extremely common particularly on the hands and feet. Warts can induce hard, thickened skin, black pinpoints, pain or tenderness with significant morbidity for the patients. Despite the presence of several therapeutic options, treatment of warts can present a challenge and they are not uniformly effective. 1 Trichloroacetic acid (TCA) causes destruction of tissue by defolding proteins in the cells. Cryotherapy is the most com- mon treatment performed by physicians for plantar warts. In this study, we aim to compare the clinical effectiveness and safety of 40% TCA solution and cryotherapy in the treatment of verruca plantaris. METHODS Participants In this study, we included patients with plantar warts attending the Dermatology Department of Bezmialem Vakif University Hospital between February and April 2015. The study was approved by the local ethics committee of Bezmialem Vakif University, Istanbul, and signed informed consent was obtained from participants and parents of the participants if a patient was younger than 18 years old. The exclusion criteria for the clinical trial were as follows: (i) immunosuppression; (ii) preg- nancy or breastfeeding; (iii) secondary infection; (iv) receiving systemic treatments in the previous 6 months; (v) receiving topical treatments in the previous 2 weeks; and (vi) severe medical conditions (liver, autoimmune, hematological). Sixty- five patients (10 patients aged <18 years, 55 patients aged ≥18 years) with a minimum of five lesions, and no longer than 18 months duration, who were willing to return for follow-up visits were enrolled in this study. Of 65 participants, 33 partici- pants were randomly assigned to cryotherapy, 32 were assigned to the 40% TCA group. Cryotherapy was performed by the same physician with a liquid nitrogen spray without peeling before application; two freeze–thaw cycles each 15 s in duration for the application were performed biweekly. TCA 40% solution was applied to the patients by the same physician weekly for 1 month with- out peeling, and the participants were advised not to wash the TCA off for 4 h after application. In both of the treatment options, five visits and four interventions were arranged. The number of lesions were recorded and lesions were photographed at each visit. Itching, local pain during applica- tion, ulceration and scarring were assessed at the end of five visits. In accordance with Pezeshkpoor et al., 2 improvement in treatment responses were classified into four groups: (i) no change (no changes in the number of warts); (ii) mild (clearing of <25% of warts); (iii) moderate (clearing of 25–75% of warts); and (iv) good (clearing of >75% of warts). Statistical analysis Statistical analysis was performed using Student’s t-test, v 2 -test and Mann–Whitney U-tests using SPSS version 15 Correspondence: Fatma Pelin Cengiz, M.D., Department of Dermatology, Bezmialem Vakif University Hospital, Adnan Menderes Boulevard, 34710 Istanbul, Turkey. Email: fpelinozgen@hotmail.com Received 14 January 2016; accepted 16 February 2016. 1 © 2016 Japanese Dermatological Association doi: 10.1111/1346-8138.13370 Journal of Dermatology 2016; : 1–3