Analysis of absorption and spreading of moisturizer on the microscopic region of the skin surface with near-infrared imaging

Quantitative skin surface hydration measurement by visible optical image processing: A pilot study

BACKGROUND

Skin barrier function is significantly impacted by skin moisture. Most non-invasive evaluation techniques to measure skin surface hydration relying on its electrical properties, which are limited in scope and have unstable operations. Applying image processing for skin hydration assessment is uncommon, with an emphasis on skin-capacitive pictures and near-infrared images in general, which demand a certain spectrum. As a result, there is an increasing need for wide-area skin hydration evaluation and mapping.

OBJECTIVE

The study aims to propose a quantitative evaluation algorithm for skin surface hydration from visible-light images.

MATERIALS AND METHODS

Three devices were applied to measure skin hydration: skin image capture device and two recognized commercial skin devices. A digital image processing system creates a new index, called GVR, to symbolize skin surface moisture. The CLAHE algorithm was applied to enhance the contrast of skin image, and after calculating it with the monochrome image, the skin reflectance image was segmented. The GVR was estimated using the values of the individual sites and the entire skin. The correlation coefficient between the three methods was examined using statistical analysis to assess the performance of GVR.

RESULTS

Skin hydration estimated from visible-light images is influenced by the entire facial structure in addition to specific areas. The electrical and visible image evaluations showed a strong association with a significant difference.

CONCLUSION

It was discovered that reflecting measures from visible images provide a quick and efficient way to quantify the moisture of the skin's surface.

The application of label-free imaging technologies in transdermal research for deeper mechanism revealing

The penetration behavior of topical substances in the skin not only relates to the transdermal delivery efficiency but also involves the safety and therapeutic effect of topical products, such as sunscreen and hair growth products. Researchers have tried to illustrate the transdermal process with diversified theories and technologies. Directly observing the distribution of topical substances on skin by characteristic imaging is the most convincing approach. Unfortunately, fluorescence labeling imaging, which is commonly used in biochemical research, is limited for transdermal research for most topical substances with a molecular mass less than 500 Da. Label-free imaging technologies possess the advantages of not requiring any macromolecular dyes, no tissue destruction and an extensive substance detection capability, which has enabled rapid development of such technologies in recent years and their introduction to biological tissue analysis, such as skin samples. Through the specific identification of topical substances and endogenous tissue components, label-free imaging technologies can provide abundant tissue distribution information, enrich theoretical and practical guidance for transdermal drug delivery systems. In this review, we expound the mechanisms and applications of the most popular label-free imaging technologies in transdermal research at present, compare their advantages and disadvantages, and forecast development prospects.

Pearls in Mitigating Application Pain of Topical Nonsteroidal Agents

BACKGROUND

Topical steroid-sparing agents (SSA), such as tacrolimus, pimecrolimus, and crisaborole, represent an important therapeutic option in the treatment of inflammatory dermatoses such as atopic dermatitis. While these agents lack the common side effects associated with topical corticosteroids, they all share application site pain as an important adverse effect.

SUMMARY

Based on the available evidence and our experience, we suggest the following 7 practical strategies for decreasing the pain associated with SSA use. (1) Use a topical corticosteroid for a few days to reduce inflammation before starting the SSA treatment. (2) Use SSAs strategically. (3) Apply moisturizer before applying SSAs. (4) Store moisturizers in the refrigerator. (5) Ask the patient to apply the SSA on a small test area before broader application. (6) Apply the SSA on dry rather than on damp skin. (7) Consider using aspirin when appropriate for the patient.

Changes in facial moisture distribution and feelings of moisture/dryness among various environmental temperatures and humidities in summer and winter

BACKGROUND

As environmental conditions vary depending on area of residence, consideration of environmental temperature and humidity conditions is crucial for detection of actual skin conditions in daily life. In this study, we determined changes in facial moisture and sensory evaluation distributions in various environmental temperature and humidity conditions.

MATERIALS AND METHODS

An original near-infrared (NIR) imaging system was used to obtain moisture distributions. Sensory evaluations of feelings of moisture/dryness were graded, and changes were compared among 10 healthy Japanese female subjects in four different environmental temperature and humidity conditions (28°C, 60% RH; 28°C, 20% RH; 15°C, 60% RH; 15°C, 20% RH) in summer and winter.

RESULTS

Skin moisture was lower at high temperatures and higher at low temperatures. Feelings of dryness on bare skin were high in low humidity. Sensitivity of feelings of moisture and dryness was high around the center of the cheekbones between side of the eyes and the mouth, but the same was not true of the moisture distribution. Moisture level was lower in winter at high temperatures, especially under the eyes near the side of the nose ridge, while the sense of dryness was not strong. These divergences between sensory evaluation and moisture level indicate the presence of a "hidden dry situation."

CONCLUSION

Changes in moisture level and sensory evaluation scores in facial skin varied among environmental conditions, which differed between summer and winter, even under the same environmental temperature and humidity.

Facial skin mapping: from single point bio-instrumental evaluation to continuous visualization of skin hydration, barrier function, skin surface pH, and sebum in different ethnic skin types

Dry skin is one of the most important concerns of consumers worldwide. Despite huge efforts over several decades, the personal care industry still does not offer a perfect solution to satisfy the unmet needs of consumers for moisturising treatments in different ethnic groups. The paucity of data for the underlying cellular and biochemical problems in, and the effects of moisturisers on photodamaged facial skin may partly explain this. Mainly, single point measurements are used to understand the effects of products on skin physiology even on surrogate skin sites such as the non‐photodamaged volar forearm. Some groups have developed discontinuous facial maps of skin biophysical properties, however, in 2014 a continuous facial analysis of bio‐instrumental evaluations was developed using a heat map approach. These maps enabled a continuous visualization of features that not only revealed an unexpected complexity of facial skin but also indicated that use of surrogate skin sites for facial skin is inappropriate. We have demonstrated that remarkable gradients of skin hydration, TEWL, skin surface pH and sebum exist within short distances across the face and the gradients are distinctive among different ethnic groups. In addition, these studies have demonstrated that darkly‐pigmented individuals do not necessarily have a better skin barrier function than their less‐pigmented counterparts and that Caucasians have a lower facial skin surface pH compared with more pigmented subjects. Overall, there are no correlations between capacitance, TEWL and skin surface pH including individual topology angle values. Novel 3D camera approaches have also been used to facilitate a more precise assignment of measurement sites and visualisation. The 3D facial colour mappings illustrated precisely the local moisturising effects of a moisturising cream. There were subtle ethnic differences in efficacy that may be related to underlying skin biochemistry and/or ethnic differences in product application. A placebo‐controlled study using conductance measurements in Chinese subjects is also reported. Finally, a new whole face statistical approach has been taken to prove differences in skin parameters but also of moisturiser treatment that adds further to our understanding of the ethnic differences in skin physiology and product application. This paper reviews the background of the development and application of this methodology.