Journal of

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Background and Aim: Common wart is a viral infection of epithelial tissues caused by human papiloma virus (HPV). In order to increase the efficacy and concurrent reduction of complications, different types of combination therapies have been recommended. One of them is the combination of cryotherapy with cantharidin. As cantharidin causes little pain and leaves small scars, we decided to design and conduct a randomized, controlled trial to investigate the efficacy of combined cryotherapy and topical cantharidin versus cryotherapy and a topical placebo. The mean number of the treatment sessions and complications of treatments were also compared between the two groups. Methods: This study was a randomized, controlled double blind clinical trial in which 110 patients with verruca vulgaris were randomly allocated into two groups. After cryotherapy in both groups, topical lotion of cantharidin 0.7% (Canthacur) and flexible collodion as placebo were applied topically in the intervention and control groups, respectively. Patients were followed for healing rates, complications and recurrence of the lesions. Results: The healing rates of lesions in both groups were 100%. The mean number of treatment sessions in the intervention and control groups were 3.4 and 4.7, respectively (P<0.001). The incidence of hyperpigmentation in the intervention and control group were 29.1% and 10.9%, respectively (P=0.017). Atrophic scars in the case group were less common than the control group (9.1% versus 29.1%). Within 4 weeks of follow up after completion of the treatment protocol, the frequency of other complications and recurrence of the lesions showed no statistically significant difference between the two groups. Conclusions: Combination of cryotherapy and cantharidin reduced the number of treatment sessions and atrophic scars, but increased the hyperpigmentation. Also, this combination therapy was ineffective in reducing other complications and the recurrence rate of the lesions.

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Background and Aim: Warts are benign tumors caused by different types of human papillomavirus. Different methods are used in the treatment of warts. The aim of this study was to compare the effectiveness, side effects and number of treatment sessions of CO₂ laser and cryotherapy in the treatment of plantar warts

Methods: Seventy patients (140 feet) with plantar warts on both feet who referred to the dermatology clinic of Farshchian (Sina) Hospital in Hamadan during 2019-2020 were selected by convenience sampling method. The warts were randomly treated with either CO₂ laser or cryotherapy on each foot. After treatment, patients were evaluated every two weeks for up to five sessions for requirement of treatment repetitions and assessment the extent of healing. In the cases with
non-healing lesion, treatment was repeated once every two weeks for up to five sessions. 

Results: The mean age of the patients was 22.11±8.73 years, and 35.7% were male and 64.3% were female. In the CO₂ laser and cryotherapy groups, the frequency of recovery rate was 81.4% and 41.4%, (P<0.001), and the mean number of treatment sessions was 1.90±0.84 and 3.55±0.69 (P<0.001) respectively. Frequency and type of side effects in the CO₂ laser and cryotrapy group was pain 25.7% and 94.3% (P<0.001), itching zero and 32.9% (P<0.001), blisters 2.9% and 82.9% (P<0.001) and hyperpigmentation with zero and 12.9% (P=0.003), respectively.

Conclusion: CO₂ laser is more effective than cryotherapy in less number of sessions and with less side effects for the treatment of plantar warts

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Cutaneous warts are among the most common benign skin lesions and, due to their high prevalence, risk of infection, and cosmetic concerns, they remain a frequent focus of clinical attention. Among the available treatment modalities, cryotherapy is widely used as a first-line option owing to its simplicity, low cost, and high success rate. However, the optimal choice of probe temperature and freeze duration still largely relies on clinical experience, and uncertainties in tissue thermal parameters may result in incomplete treatment or unintended damage to surrounding healthy tissue.
In this study, a numerical model was developed to investigate the temperature distribution within human skin during the cryotherapy of warts. The model is based on the radial heat-conduction equation and incorporates temperature-dependent thermophysical properties of human skin as reported by Agafonkina et al. (2021). Simulations were performed for a range of probe surface temperatures between -30 °C and -70 °C, and the temporal evolution of the wart center temperature was examined until it reached the cellular destruction threshold. The results indicate that lowering the probe temperature accelerates the freezing process; however, below approximately -55 °C, this enhancement becomes saturated and the risk of collateral tissue damage increases. Based on the obtained optimization map, the optimal probe temperature was found to lie within the interval -45 to -55 °C, for which the wart core reaches the critical temperature (-20°C) within 5 to 8 seconds. Comparison with clinical data demonstrates that the developed numerical model can serve as an effective tool for predicting and optimizing cryotherapy parameters, thereby improving treatment precision and reducing the likelihood of clinical error.