755-nm picosecond laser plus topical 20% azelaic acid compared to topical 20% azelaic acid alone for the treatment of melasma: a randomized, split-face and controlled trial.

PURPOSE: Melasma remains a refractory skin condition that needs to be actively explored. Azelaic acid has been used for decades as a topical agent to improve melasma through multiple mechanisms, however, there is a lack of research on its combination with laser therapy. This study evaluated the effectiveness of isolated treatment with topical 20% azelaic acid and its combination with 755-nm picosecond laser in facial melasma patients. METHODS: A randomized, evaluator-blinded, controlled study was conducted on 30 subjects with facial melasma in a single center from October 2021 to April 2022. All subjects received topical 20% azelaic acid cream (AA) for 24 weeks, and after 4 weeks, a hemiface was randomly assigned to receive 755-nm picosecond (PS) laser therapy once every 4 weeks for 3 treatments. Treatment efficacy was determined by mMASI score evaluations, dermoscopic assessment, reflectance confocal microscopy (RCM) assessments and patient's satisfaction assessments (PSA). RESULTS: Treatment with 20% azelaic acid, with or without picosecond laser therapy, significantly reduced the hemi-mMASI score (P < 0.0001) and resulted in higher patient satisfaction. Improvements in dermoscopic and RCM assessments were observed in both sides of the face over time, with no difference between the two sides. RCM exhibited better dentritic cell improvement in the combined treatment side. No patients had serious adverse effects at the end of treatment or during the follow-up period. CONCLUSION: The additional use of picosecond laser therapy showed no clinical difference except for subtle differences detected by RCM assessments.The study was registered in the Chinese Clinical Trial Registry (ChiCTR2100051294; 18 September 2021).

3D error calibration of spatial spots based on dual position-sensitive detectors.

In this paper, a dual position-sensitive detector-based vision measurement system camera is built instead of a traditional CCD camera. The 3D position information for the light point is calculated according to the 2D coordinate information of a certain light point in the space illuminated on the two position-sensitive detector (PSD) photosensitive surfaces, which is used for position detection of the spatial light point. In addition, the positioning model for 2D PSDs with different spot sizes in the Gaussian spot mode is derived by the mathematical model of Lucovsky's differential equation for a PSD. For the nonlinear distortion of the PSD, a nonlinear error calibration method using a particle swarm combined with a back propagation neural network is proposed to correct the errors in the measured values through the relationship between the input and output values, to obtain the predicted value that approximates the real coordinates. Then, by comparing the influence of different spot sizes on the positioning accuracy, we conclude that the smaller the spot formed by the convergence of the beam under the optical lens, the higher the positioning accuracy. We believe this conclusion can help improve the accuracy of PSD measurements. Finally, a red LED light spot is set up, and the 3D position measurement and error calibration of the light spot is done by dual PSD cameras, which better solves the position detection problem of a space light spot under close-range conditions because it is fast, reliable, and easy to implement. It also provides an effective method to detect the motion trajectory of a moving light spot in space.

Investigation on the Awareness and Behavior of Primary School Students on Sunscreen Use in Beijing.

Objective: This study aims to understand primary school students' behavior and awareness of sun exposure and sunscreen in Beijing, China. Methods: A questionnaire survey was conducted of 232 students in grades 4-6 at a public primary school in Beijing, including 129 boys (55.6%) and 103 girls (44.4%). The contents of the questionnaire included awareness about ultraviolet rays, sun exposure, sunscreen habits, and the understanding and use of sunscreen. Results: The majority of the subjects (75.0%) said they had never been sunburned, and 26.3% had never been tanned. Only 7.3% of the primary school students had a comprehensive and correct understanding that sunlight will burn, cause cancer, tan, and age the skin. Sunscreen (47.8%), sunshades (47.4%), sun hats (44.4%), avoiding going out at noon (37.5%), and sunglasses (30.2%) were the most frequently used sunscreen means. Furthermore, 47.8% of primary school students used topical sunscreen for light protection, higher than other measures. The proportion of girls using sunscreen at least once a day was more than boys. Conclusion: Primary school students in Beijing, China, do not have a comprehensive understanding of ultraviolet rays, and there are deficiencies in protective behavior. Their awareness and use of sunscreen need to be improved.

Delayed complication of botulinum toxin and hyaluronic acid filler injections: A case report.

BACKGROUND: Botulinum toxin and hyaluronic acid (HA) filler injections are popular minimally invasive cosmetic procedures owing to their convenience, efficiency, and durability; however, adverse reactions often occur. MATERIALS AND METHODS: We describe the delayed hypersensitivity reaction that occurred after sequential injections of botulinum toxin and HA filler. RESULTS: The histopathologic and dermatoscopic findings suggested a delayed hypersensitivity reaction with the formation of a dermal foreign body granuloma. The rash resolved 2 months following treatment with antihistamines and topical steroids cream. CONCLUSION: We assume that local trauma during the blepharoplasty stimulated an immune response, which was the basis for this complication.

Laser therapy in the treatment of melasma: a systematic review and meta-analysis.

Melasma is a highly prevalent and cosmetically disfiguring pigmented skin disease. The post-treatment results are often unsatisfactory. A large number of clinical trials have tried to prove the effectiveness of the combination therapy involving laser therapy, but the results have been indeterminate. This study aimed to evaluate the effectiveness of laser treatment for melasma via a systematic review and meta-analysis. We respectively searched 4 databases and clinicaltrials.gov as of June 8, 2021. Two researchers independently searched for literature and extracted data. Study outcomes were computed by weighted mean differences (WMD). All statistical analyses were performed by the Review Manager version 5.3, STATA version 14 software at 95% confidence interval. We obtained 22 eligible studies which involved a total of 694 patients. After the heterogeneity test and sensitivity analysis, we took a subgroup meta-analysis on the before and after treatment of different laser types. We found that most lasers and laser-based combinations were associated with reduced melasma area and severity index (MASI), such as low-fluence Q-switch 1,064-nm Nd: YAG laser (QSNYL) (WMD: - 2.76; 95% CI: - 3.53 to - 1.99), fractional ablative CO2 laser (WMD: - 9.36; 95% CI: - 12.51 to - 6.21), and fractional ablative 2940-nm Er: YAG laser (WMD: - 2,72; 95% CI: - 3.94 to - 1.49). Significant decrease was seen in neither MASI score of non-ablative 1550-nm fractional laser (WMD: - 1.29; 95% CI: - 2.80 to 0.21) and picosecond laser (WMD: - 0.58; 95% CI: - 1.43 to 0.27), nor melanin index (MI) of low-fluence QSNYL treatment (WMD: 10.17; 95% CI: - 4.11 to 24.46). When using laser to treat melasma, various adverse reactions may occur, most of which will resolve quickly without subsequent treatment, such as edema, erythema, scaling, and burning sensation after treatment. However, for patients with darker skin, there are risks of postinflammatory hyperpigmentation and hypopigmentation. The laser and laser-based combination treatment for melasma could significantly reduce the MASI score, which was showed by our systematic review and meta-analysis.

Time trends of contact allergy to a modified European baseline series in Beijing between 2001 and 2006.

BACKGROUND: Monitoring trends of sensitivity rates in a population is useful for epidemiological surveillance. The time trends for sensitivity rates of allergens have not previously been reported in China. OBJECTIVES: The aim of the present study was to determine the prevalence and trends of contact allergy in patients with suspected allergic contact dermatitis in Beijing, China. PATIENTS/METHODS: A retrospective analysis of all patch test data from our database was performed. A total of 1354 patients with suspected allergic contact dermatitis between 2001 and 2006 were studied. Patch tests with 20 allergens or mixtures of allergens were performed and analysed. RESULTS: Sensitivity to potassium dichromate (50.1%) was most frequent, and sensitivity to imidazolidinyl urea (3.0%) was least frequent. Increasing trends in sensitivity rates for 10 allergens with significant linear regression were observed (p < 0.05), including mercapto mix, black rubber mix, potassium dichromate, formaldehyde, epoxy resin, benzocaine, ethylenediamine dihydrochloride, paraben mix, tixocortol-21-pivalate, and sesquiterpene lactone mix. Sensitivity rates for the other 10 allergens remained stable or showed only a trend (fragrance mix) towards an increase (p(trend) > 0.05). CONCLUSIONS: High sensitivity rates were observed in the study. Significant increasing trends in sensitivity rates for 10 allergens, probably reflecting increasing changes in exposure, were found.

Randomized trial of the impact of a sun safety program on volunteers in outdoor venues.

BACKGROUND: A suitable sun safety educational program could help the public avoid sun exposure-induced skin damage. The objective of this study was to assess the impact of a sun safety program on volunteers in outdoor venues and explore the most effective sun safety education method in China. METHODS: An intervention program was implemented to raise knowledge and behavior regarding sun exposure among volunteers in the outdoor competition venues in Beijing, China. Five intervention methods were used, including class education, free sunscreen samples, pamphlets, posters, and newsletters. The self-administered multiple-choice questionnaires were administered before and after the intervention. RESULTS: Two hundred and eighty-five subjects were enrolled, including 107 males (37.5%) and 178 females (62.5%). The intervention group showed improvement in sun safety knowledge and behavior. Other improvements were achieved in the field of sun safety awareness and intended behavior, with most of the items achieving no statistically significant differences. Subgroup A (multi-component interventions, including class education, free sunscreen samples, and written materials) achieved better results than subgroup B (written materials only) to improve sun safety knowledge and awareness. CONCLUSION: Sun safety education could improve volunteer 's sun safety knowledge and behavior in the outdoor venues in China. Multi-component interventions proved to be the most effective sun safety education method.

Sun-exposure knowledge and protection behavior in a North Chinese population: a questionnaire-based study.

BACKGROUND: Sun exposure can cause a range of skin disorders. Skin damage can be prevented by following certain sun-protection measures. However, the majority of reported studies regarding sun-exposure knowledge and behavior have involved Caucasian populations. METHODS: A self-administered multiple-choice questionnaire was administered. The questionnaire consisted of 13 questions aimed at evaluating people's knowledge, awareness, and protection behavior regarding sun exposure, and their knowledge of sunscreens and sunscreen use. RESULTS: A total of 623 volunteers were enrolled, including 238 men (38.2%) and 385 women (61.8%). The percentages of correct answers regarding sun-exposure knowledge and awareness ranged from 50% to 80%. Overall, 58.8% used sunscreen as a sun-protection measure in daily life, followed by use of protective clothes (49.3%), sun umbrella (45.4%), sunglasses (45.3%), and hat (42.2%). Fifty-two percent thought that suntan was harmful or not attractive. The mean sun-protection factor (SPF) of the sunscreens used was 27.7 +/- 9.2 and the mean UVA protection grade (PA) was 2.3 +/- 0.6. CONCLUSIONS: Knowledge and awareness concerning the harmful effects of sun exposure are widespread among the Chinese population. Sunscreens with high SPF and PA are the most commonly used among Chinese people. Clear sex differences were observed. There is a significant difference in the attitude toward suntan between Chinese and Caucasian populations.