Cowhage-induced itch scores and the current perception threshold in assessing sensitive skin: An observational laboratory study.

BACKGROUND: The diagnosis of sensitive skin remains nonuniform, and the underlying mechanism is unclear. Previous studies were inconsistent in the current perception threshold (CPT) measurement for sensitive skin; thus, the neural sensitivity of sensitive skin needs to be clarified. OBJECTIVES: This study aimed to compare the CPT measurement and the cowhage test for sensitive skin and to investigate the correlation between CPT values and cowhage-itch scores. METHODS: Participants with and without sensitive skin (n = 30, 30) were included. The cowhage test and CPT measurement with its related sensations were performed. RESULTS: No difference was found in CPT between the sensitive and nonsensitive groups at either the site of the face or the forearm (5, 250, or 2000 Hz). Once the CPT was reached, sensations (itch, stinging, and throbbing) were significantly different between the two groups. Cowhage provoked more intense itch with a longer duration in the face (visual analog scale [VAS] score 1.90 ± 1.47 vs. 0.52 ± 0.90, p < 0.001; duration 3.80 ± 3.31 vs. 0.87 ± 1.43 min, p < 0.001) and forearm (VAS 2.53 ± 2.60 vs. 0.72 ± 1.06, p < 0.001; duration 3.37 ± 3.46 vs. 1.33 ± 2.14 min, p < 0.01) of the sensitive group compared with the nonsensitive group. Cowhage-induced itch and CPT-related itch (5 Hz) showed moderate correlations in both the face (r = 0.441, p < 0.001) and forearm (r = 0.491 p < 0.001) and weak correlations in the forearm (r = 0.323 at 250 Hz, p = 0.012; r = 0.376 at 2000 Hz, p = 0.003). CONCLUSIONS: Cowhage test showed better performance in assessing the neural sensitivity of sensitive skin in comparison with the CPT measurement. Evaluation of CPT-related sensations may add valuable information to sensitive skin assessment.

Assessment of features in facial hyperpigmentation: Comparison study between VISIA and CSKIN.

BACKGROUND: Hyperpigmentary disorder is one of the commonest skin concerns in dermatology clinics. The availability of noninvasive instruments provided a convenient, objective, and reproducible methodology for the evaluation of pigmentation and skin color. The aim of this study is to compare CSKIN and VISIA in measuring facial hyperpigmentation, as well as to assess the correlation between the instrumental analyzing and clinical evaluation. METHODS: Eighty Chinese patients were enrolled. Images were taken and analyzed by VISIA from Canfield and CSKIN from Yanyun Technology, and the facial hyperpigmentation was graded by three dermatologists. RESULTS: Feature counts within the facial pigmented areas analyzed by VISIA showed positive correlations with brown pixels (r = 0.331, p < 0.05) and brown percent (r = 0.395, p < 0.0001) measured by CSKIN. The parameters measured by CSKIN and VISIA were significantly correlated with visual scores graded by the dermatologists, with VISIA presenting a moderate correlation (r = 0.509, p < 0.001) and CSKIN a slightly stronger correlation with the visual scores (r = 0.653, p < 0.001). CONCLUSION: CSKIN could serve as an alternative in the assessment and follow-up of skin disease featuring with facial hyperpigmentation.

Effectiveness of a Radiofrequency Device for Rejuvenation of Aged Skin at Home: A Randomized Split-Face Clinical Trial.

INTRODUCTION: Several techniques, including the use of radiofrequency (RF) devices, are currently utilized for the treatment of skin aging. This study aimed to evaluate the anti-aging effects imparted by a home-based RF beauty device and to compare these results with those of a marketed anti-aging cosmetic in vivo. METHODS: Thirty-three women aged 35-60 years were enrolled in this randomized, controlled, split-face trial. This study involved a 12-week trial with five repeated measurements (at baseline, 2, 4, 8 and 12 weeks). One side of the face was randomly selected to be part of the experimental group and treated with the RF beauty device, while the other side was considered as control and was treated with an anti-aging cosmetic. Treatment safety was evaluated. Skin wrinkles, hydration, radiance, elasticity, color and thickness were evaluated using noninvasive equipment. RESULTS: Thirty-two participants completed the study; one withdrew for personal reasons. Compared with the anti-aging cosmetic-treated facial side, the experimental side showed statistically significant improvements in wrinkles, skin radiance, color and thickness (p < 0.05). CONCLUSIONS: The home-based RF beauty device was safe and effective for rejuvenation. The device was more effective than the commercially available anti-aging cosmetics.

Characterization of Cowhage-induced Pruritus in Sensitive Skin: An Observational Laboratory Study.

Sensitive skin is a prevalent syndrome, characterized by discomfort in response to mild stimuli, which impacts on quality of life. Pruritus is one of the major symptoms of sensitive skin. However, the pathomechanism of sensitive skin is insufficiently understood. As an experimental model for pruritus, the cowhage skin prick test might provide insight into the understanding of sensitive skin. This study aimed to specify the characteristics of cowhage-induced pruritus in sensitive skin. Female volunteers, 20 with sensitive skin and 20 controls, were recruited. Self-report questionnaires were distributed and the responses evaluated; moreover, alongside assessments by dermatologists, skin physiology assessments, lactic acid sting test, capsaicin test and cowhage skin challenge were performed. Pruritus in sensitive skin was perceived as more intense and longer-lasting than in normal skin, with different qualities of accompanying sensations. Cowhage skin challenge results showed moderate consistency with clinical assessments. The results suggest that cowhage skin challenge could be a new tool for the assessment of sensitive skin.

Cellulose Nanocrystals for Skin Barrier Protection by Preparing a Versatile Foundation Liquid.

Most of the foundation liquids in the market need makeup removers for cleaning, while the excessive use of makeup removers might lead to skin barrier damage, which would further lead to many kinds of dermatosis, such as skin sensitivity, facial telangiectasia, rosacea, acne, as well as various cosmetic contact dermatitis. Inspired by the protective effect of fiber-rich diet on the intestinal mucosal mechanical barrier, a novel hemp/cellulose nanocrystals (CNCs)-based foundation liquid featuring easy-wiping property has been constructed, which will effectively solve the post-makeup skin cleaning problems. In this experiment, the formula of the foundation liquid can be obtained through hemp/CNCs instead of mineral oil and titanium oxide, which are considered to have undesirable local tolerance, sensitizing potential, and are environmental pollutants, to create a moisture barrier. Industrial hemp is a hot issue in cosmetic research, and a great quantity of discarded industrial hemp stalk is available to be used to produce hemp/CNCs through grinding and acidification. The graft technique is adapted to obtain hemp/CNCs-g-polylactic acid (PLA). By replacing the hydroxyl group on the side of hemp/CNCs, hemp/CNCs-g-PLA reduces the intermolecular hydrogen bonding, resulting in a higher dispersion in the oil phase. The hemp/CNCs-g-PLA has excellent performance in terms of biological compatibility, water resistance, and non-penetration into the skin. With basic features of a foundation liquid to alleviate discoloration, age spots, and skin roughness, the foundation liquid based on hemp/CNCs-g-PLA provides a novel characteristic of easy-wiping, which helps to avoid the damage to the skin barrier caused by excessive cleansing.

Short-term skin reactions following use of N95 respirators and medical masks.

BACKGROUND: In the context of the COVID-19 pandemic, cases of adverse skin reactions related to the wearing of masks have been observed. OBJECTIVES: To analyze the short-term effects of N95 respirators and medical masks, respectively, on skin physiological properties and to report adverse skin reactions caused by the protective equipment. METHODS: This study used a randomized crossover design with repeated measurements. Twenty healthy Chinese volunteers were recruited. Skin parameters were measured on areas covered by the respective masks and on uncovered skin 2 and 4 hours after donning, and 0.5 and 1 hour after removing the masks, including skin hydration, transepidermal water loss (TEWL), erythema, pH, and sebum secretion. Adverse reactions were clinically assessed, and perceived discomfort and non-compliance measured. RESULTS: Skin hydration, TEWL, and pH increased significantly with wearing the protective equipment. Erythema values increased from baseline. Sebum secretion increased both on the covered and uncovered skin with equipment-wearing. There was no significant difference in physiological values between the two types of equipment. More adverse reactions were reported following a N95 mask use than the use of a medical mask, with a higher score of discomfort and non-compliance. CONCLUSIONS: This study demonstrates that skin biophysical characters change as a result of wearing a mask or respirator. N95 respirators were associated with more skin reactions than medical masks.