Abstract: 【Abstract】 Objective To investigate the clinical efficacy and safety of needle-free and needle-based injections of recombinant human interferon （IFN）-α2a in the treatment of palmoplantar warts. Methods Patients aged 6 to 75 years with palmoplantar warts were prospectively enrolled from the Department of Dermatology, Zhongda Hospital, Southeast University between March and September 2023, and baseline data were collected. The patients were randomly and equally divided into a needle-free injection group and a needle-based injection group by using a random number table method, and received needle-free and needle-based injections of recombinant human IFN-α2a once every 2 to 3 weeks, respectively, with a maximum of 4 treatment sessions. Efficacy was assessed based on changes in wart size and skin lines under a dermoscope. Pain degrees and adverse reactions were recorded, and patients were followed up for 6 months after the end of treatment. Chi-square test was used to compare the cure rates, recurrence rates, and incidence rates of adverse reactions between the two groups. Logistic regression analysis was employed to identify factors related to the clearance of palmoplantar warts. Results A total of 160 patients with palmoplantar warts were included, with 80 patients in each group. In the needle-free injection group, there were 45 females （56.2%） and 35 males （43.8%）; their ages （M［Q1, Q3］） were 27 （23, 40） years, and the duration of disease （M［Q1, Q3］） was 12 （3, 24） months; warts were located on the hands in 12 cases （15.0%）, on the feet in 60 cases （75.0%）, and on both sites in 8 cases （10.0%）; warts measuring ≤ 1 cm in diameter were observed in 71 cases （88.8%）, and those measuring > 1 cm were observed in 9 cases （11.3%）. In the needle-based injection group, there were 37 females （46.2%） and 43 males （53.8%）; their ages were 28 （22, 39） years, and the duration of disease was 6 （2, 12） months; warts were located on the hands in 23 cases （28.7%）, on the feet in 55 cases （68.8%）, and on both sites in 2 cases （2.5%）; warts measuring ≤ 1 cm in diameter were observed in 67 cases （83.8%）, and those measuring > 1 cm in diameter were observed in 13 cases （16.3%）. There were no significant differences in gender distribution, age, wart diameters, prior treatment status, or number of warts between the two groups （all P > 0.05）. The duration of disease was longer in the needle-free injection group than in the needle-based injection group （P = 0.041）, and the dose of interferon was lower in the needle-free injection group than in the needle-based injection group （P < 0.001）. After treatment, 44 patients （55.0%） were cured in the needle-free injection group, and 39 （48.8%） in the needle-based injection group, with no significant difference in the cure rates between the two groups （χ2 = 0.63, P = 0.429）. Among patients with multiple warts, 54.8% （23/42） were cured in the needle-free injection group, and 47.4%（18/38） in the needle-based injection group, with no significant difference in cure rates between the two groups （χ2 = 1.28, P = 0.509）. The most common adverse reaction was fever or flu-like symptoms （186 instances）, which resolved spontaneously in 141 instances and resolved after treatment with oral ibuprofen in 45 instances; the incidence rate of flu-like symptoms was significantly lower in the needle-free injection group （57 instances, 21.6%） than in the needle-based injection group （129 instances, 53.3%; χ2 = 54.63, P < 0.001）. The pain score was significantly lower in the needle-free injection group （3.65 ± 1.25 points） than in the needle-based injection group （5.16 ± 1.17 points, t = -7.90, P < 0.001）. The logistic regression analysis showed that the duration of disease, lesion sites, patient age, and previous treatment history had no impact on the efficacy in either the needle-free injection group or the needle-based injection group （all P > 0.05）. Conclusions The efficacy of needle-free and needle-based injections of interferon was similar in the treatment of palmoplantar warts, whereas needle-free injections resulted in less pain and a lower incidence of interferon-related adverse reactions. None of the duration of disease, lesion sites, patient age, or prior treatment status showed significant impact on the efficacy in the two groups.

Key words: Warts, Interferon alpha-2, Dermoscopy, Needle-free injection, Palmoplantar warts