Abstract: 【Abstract】 Objective To evaluate clinical efficacy and safety of microneedle-mediated intradermal injection with hyaluronic acid for the treatment of sensitive skin. Methods A total of 53 female patients aged 21 - 54 years and diagnosed with sensitive skin were enrolled from Department of Cosmetic Dermatology, Dermatology Hospital of Southern Medical University from January to June in 2018, and were divided into 3 groups by using a random number generator and a residue-based method: high-pressure jet injection group （n = 23） receiving high-pressure jet injection with hyaluronic acid on the right side of the face （treatment side） and high-pressure jet injection with 0.9% sodium chloride solution on the left side of the face （control side） once every 2 weeks, microneedle injection group （n = 15） receiving microneedle-mediated injection with hyaluronic acid on the right side of the face （treatment side）and microneedle-mediated injection with 0.9% sodium chloride solution on the left side of the face （control side） once every 4 weeks, combination group （n = 15） receiving microneedle-mediated injection with hyaluronic acid on the right side of the face （treatment side） and high-pressure jet injection with hyaluronic acid on the left side of the face （control side） once every 4 weeks. All the patients in the above 3 groups received 4 consecutive sessions of treatment. Before the initial treatment and 2 weeks after the final treatment, erythema and skin pore scores were determined on the right and left sides of the face by using VISIA facial imaging system, lactic acid stinging test was performed, and skin sensitivity including severity of itching, dryness, erythema and scaling was evaluated. Two weeks after the final treatment, the overall improvement was evaluated with the Global Aesthetic Improvement Scale（GAIS）by clinicians and patients. Adverse reactions were recorded during and after treatment. Statistical analysis was carried out by using paired t test, Wilcoxon sign rank sum test and chi-square test. Results Two weeks after the final treatment, the improvement of skin pore score in the treatment side was superior to that in the control side in the high-pressure jet injection group （t = 2.19, P = 0.03）, while no significant difference in the improvement of erythema score was observed between the treatment side and control side（t = 1.10, P = 0.27）; in the microneedle injection group, the improvement of erythema and skin pore scores was greater in the treatment side than in the control side （t = 2.47, 3.02, both P = 0.01）; in the combination group, the VISIA erythema score in the treatment and control sides was 0.59 ± 0.25 and 0.85 ± 0.31 respectively, the improvement of erythema score in the treatment side was superior to that in the control side （t = 5.02, P < 0.01）, while there was no significant difference in the improvement of skin pore score between the treatment side and control side （P > 0.05）. Two weeks after the final treatment, the severity of itching, dryness and scaling was significantly improved in both the treatment and control sides in the 3 groups compared with those before the initial treatment （P < 0.05）, while the severity of erythema was significantly improved only in the treatment side in the microneedle injection group and combination group when compared with that before the initial treatment （Z = -2.236, -2.887, respectively, both P < 0.05）. Moreover, both the microneedle injection group and combination group showed significantly decreased severity of erythema in the treatment side compared with that in the control side two weeks after the final treatment （Z = -2.646, -2.887, respectively, both P < 0.05）. Two weeks after the final treatment, the positive rate of the lactic acid stinging test significantly decreased in the treatment side compared with that before the initial treatment in the microneedle injection group （χ2 = 4.821, P = 0.028）, but showed no significant changes in the other groups （all P > 0.05）. No severe adverse reactions were observed during or after the treatment. Conclusion Microneedle intradermal injection with hyaluronic acid can effectively and safely improve erythema, skin pore and sensitive symptoms in patients with sensitive skin.

Key words: Injections, jet, Hyaluronic acid, Sensitive skin, Microneedle- mediated injection, High-pressure jet, Split-face study