Differences In Skin Structure Research Articles

Gender differences in allergic contact dermatitis to common allergens.

Gender-based differences in skin structure, physiology, and allergen exposure can influence contact dermatitis development. This study investigated the differences and trends in contact sensitizers, focusing on the top 10 allergens and personal care product (PCP) contact allergies from a gender perspective. We conducted a retrospective chart review of 5998 patients undergoing patch testing at an occupational and contact dermatitis clinic in a Thai, university-based, tertiary referral hospital from January 2001 to December 2021. Patients' characteristics and patch test results were collected. Females had a higher positive patch test rate than males (71.8% vs. 65%, p < 0.001). However, males showed a greater prevalence of occupationally related allergic contact dermatitis (15.9%). Multivariate analysis revealed associations between being female and allergies to colophonium (aOR 1.46, 95% CI 1.07-1.99, p = 0.019), formaldehyde (aOR 1.97, 95% CI 1.17-13.31, p = 0.010), fragrance mix I (aOR 1.66, 95% CI 1.34-2.07, p < 0.001), MCI/MI (aOR 2.55, 95% CI 1.90-3.44, p < 0.001), neomycin (aOR 4.15, 95% CI 2.54-6.80, p < 0.001), and nickel (aOR 2.62, 95% CI 2.17-3.15, p < 0.001). Conversely, being male correlated with allergies to carba mix (aOR 0.51, 95% CI 0.41-0.64, p < 0.001), epoxy resin (aOR 0.26, 95% CI 0.14-0.47, p < 0.001), n-isopropyl-n-phenyl-4-phenylenediamine (aOR 0.41, 95% CI 0.20-0.83, p = 0.014), paraben mix (aOR 0.42, 95% CI 0.32-0.56, p < 0.001), and potassium dichromate (aOR 0.70, 95% CI 0.58-0.84, p < 0.001). Positive reactions to PCPs stood at 13% overall (males 17.1%, females 12.2%, p < 0.001). Gender plays a pivotal role in contact dermatitis. This work emphasises the importance of considering gender-specific factors when diagnosing and managing contact allergies.

Does hyaluronidase injected in periocular area change skin ultrastructure?: Standardized in vitro analysis.

Treatment with hyaluronic acid (HA) fillers as a strategy for rejuvenation has experienced a significant growth in recent years, accompanied by a parallel increase in its complications, the treatment of which, such as hyaluronidase, we must be aware of. 14 patients (28 eyes) had indication for upper blepharoplasty surgery in the Hospital Universitario y Politécnico La Fe. After surgery, periocular skin of one eye of each patient was infiltrated with 300 U of hyaluronidase (14 cases) while the skin of the fellow eye was preserved untreated (14 controls). All samples were studied by the Pathology department, and finally, 6 variables (skin structure alteration, degeneration of elastic fibers, deposits, collagen fibers destructuring, inflammation, and other findings) were analyzed. No differences in skin structure, elastic fibers, and collagen dermal fibers were found between hyaluronidase-treated skin and controls. A significant association between ex vivo application of hyaluronidase in periocular skin and the presence of amorphous extracellular deposits within the dermis was found. Hyaluronidase applied ex vivo to periocular skin led to presence of deposits within the extracellular matrix compared to control eyelid skin but elastin and collagen dermis structure remained unaltered.

Transcriptome Analysis Reveals Candidate Genes Regulating the Skin and Hair Diversity of Xinji Fine-Wool Sheep and Tan Sheep

The hair follicle is a complex mini-organ in the skin that undergoes organ induction, morphogenesis, and regeneration. However, the accurate molecular mechanism of skin and hair diversity regulation is still elusive. The sheep is an animal model that can be used to further explore the mechanisms of skin and hair diversity. In this study, we carried out a transcriptomic analysis of the mRNA expression in the skin of Xinji fine-wool sheep at different growth stages (3 and 12 months old) and 12-month-old Tan sheep and explored the transcripts’ relationship with hair follicle growth. A total of 1327 mRNAs and 67 transcription factors were identified to be differentially expressed in the different breeds and during different periods of skin development. The differentially expressed genes were enriched in GO terms represented by system development, multicellular organism development, animal organ development, and skin development, and three KEGG pathways typified those governing differences in skin structure. Combining protein–protein interaction networks of skin development (GO:0043588) and functional annotation, nine important candidate genes, namely, LAMA5, OVOL1, SRF, DHCR24, NGFR, SMO, CDSN, HOXC13, and KDF1, and many core genes with minor effects were confirmed to be associated with hair follicle development. Furthermore, members of the zf-C2H2 and homeobox transcription factor families, which were identified to play a crucial role in producing finer and denser wool, were mainly upregulated in 12-month-old Xinji fine-wool sheep when compared with expression in 12-month-old Tan sheep and 3-month-old Xinji fine-wool sheep. This study revealed the major–minor gene interactions in the developmental pathway and provided ideas for an in-depth understanding of the genetic structure and gene regulation in the skin/hair growth process.

Chronic itch in African Americans: an unmet need.

Chronic pruritus carries a significant burden of disease and is associated with a negative impact on quality of life. African Americans are disproportionately burdened by chronic pruritic disorders, including but not limited to atopic dermatitis, prurigo nodularis, inflammatory scalp dermatoses, pathologic scarring, and HIV-related dermatoses. Racial differences in skin structure and function may contribute to the pathogenesis of itch in African Americans. Itch perception and response to treatment in African Americans remain understudied and not well understood. As such, there is a large unmet need with regard to the knowledge and management of pruritus in African Americans. This review highlights notable differences in the epidemiology, pathophysiology, genetic predisposition, clinical presentation, and response to treatment for select pruritic skin conditions. By addressing itch as an unmet need in African Americans, we hope to improve patient outcomes and lessen disparities in dermatologic care.

Optical Diagnostics of the Maxillary Sinuses by Digital Diaphanoscopy Technology.

The work is devoted to the development of a scientific and technical basis for instrument implementation of a digital diaphanoscopy technology for the diagnosis of maxillary sinus inflammatory diseases taking into account the anatomical features of patients (differences in skin structure, skull bone thickness, and sinus size), the optical properties of exercised tissues, and the age and gender characteristics of patients. The technology is based on visualization and analysis of scattering patterns of low-intensity radiation as it passes through the maxillary sinuses. The article presents the experimental data obtained using the digital diaphanoscopy method and the results of numerical simulation of the optical radiation passage through the study area. The experimental setup has been modernized through the installation of a a device for controlling the LED applicator brightness. The approach proposed may have considerable promise for creating diagnostic criteria for various pathological changes and can be used to assess the differences in the optical and anatomical features of males and females.

Role of pH Value in Clinically Relevant Diagnosis.

As a highly influential physiological factor, pH may be leveraged as a tool to diagnose physiological state. It may be especially suitable for diagnosing and assessing skin structure and wound status. Multiple innovative and elegant smart wound dressings combined with either pH sensors or drug control-released carriers have been extensively studied. Increasing our understanding of the role of pH value in clinically relevant diagnostics should assist clinicians and improve personal health management in the home. In this review, we summarized a number of articles and discussed the role of pH on the skin surface as well as the factors that influence skin pH and pH-relevant skin diseases, but also the relationship of skin pH to the wound healing process, including its influence on the activity of proteases, bacterial enterotoxin, and some antibacterial agents. A great number of papers discussing physiological pH value have been published in recent decades, far too many to be included in this review. Here, we have focused on the impact of pH on wounds and skin with an emphasis on clinically relevant diagnosis toward effective treatment. We have also summarized the differences in skin structure and wound care between adults and infants, noting that infants have fragile skin and poor skin barriers, which makes them more vulnerable to skin damage and compels particular care, especially for wounds.

Skin microbiota in women of reproductive age in norm and androgen-dependent dermatoses

The skin is the largest organ of the human body and is colonized by divergent microorganisms, with a majority of them being harmless and even helpful for humans. The development of molecular methods for the identification of microorganisms has led to a conception that the skin microflora is greatly diverse and variable. Innate and adaptive immune responses can change the microbiota, and, on the other hand, the microbiota is involved in an immune response. The degree of colonization of the skin by different microorganisms varies greatly depending on the body sites, as well as endogenous and exogenous factors. There are significant gender differences in skin structure and physiology, which is substantially influenced by sex hormones. The investigation of the skin microbial component in androgen-dependent dermatoses, such as acne and seborrheic dermatitis, will contribute to understanding the pathogenic mechanisms of these diseases and to developing effective methods of therapy.

Phonophoresis in animals- A review

Phonophoresis is a transdermal drug-delivery system that uses ultrasound to enhance the delivery of topically-applied drugs. Use of ultrasound in therapeutics and drug delivery has gained importance in recent years in human-medicine while it is still a new frontier in veterinary medicine. The primary challenge in developing these systems is rooted in the wide differences in skin structure and function seen in species ranging from cats to cows. The following review focuses on the mechanism of phonophoresis and encompasses a discussion on the possible applications of phonophoresis, phonophoretic-systems used in humans and future trends to develop a drug and species-specific phonophoretic-systems. The paper concludes with a section detailing the scope of research in future in veterinary medicine. The purpose of this article is to build a theoretical foundation for understanding phonophoresis and review the efficacy of phonophoresis as a clinical treatment in physical-therapy in humans as well as in animals.

Ethnic differences in skin structure and function

Ethnic differences in skin structure and function

Dermal exposure and changes in skin barrier function of base metal refinery workers co-exposed to cobalt and nickel

Refi nery workers are exposed to many metals, including cobalt and nickel, both of which are skin sensitisers, causing allergic contact dermatitis. Dermal exposure, and changes in skin barrier function [skin hydration, transepidermal water loss (TEWL) and skin surface pH] from start to end of shift, of base metal refi nery workers co-exposed to cobalt and nickel, were assessed. Changes in SH were inconsistent, while TEWL generally increased and SS-pH decreased. The decrease in SS-pH is most likely due to direct skin contact with sulphuric acid. Dermal exposure was variable even though workers wore personal protective gloves, highlighting the limitations of personal protective clothing in controlling exposure. None of the workers presented with allergic contact dermatitis (ACD). The small sample size of this study limits the interpretation of the absence of ACD, but the healthy worker effect and ethnic differences in skin structure and function may be contributing factors.

Morphological differences in the skin of marble trout &lt;i&gt;Salmo marmoratus&lt;/i&gt; and of brown trout &lt;i&gt;Salmo trutta&lt;/i&gt;

Despite being genetically very closely related, the marble trout Salmo marmoratus and the brown trout Salmo trutta exhibit marked phenotypic differences, particularly with regard to skin pigmentation. Histological analysis of skin from the head and gill cover of differently aged individuals of the two species was carried out in order to characterize differences in skin structure. The basic structure of skin of the individuals studied corresponded with that described for other salmonids, though the head epidermis was somewhat thicker in S. marmoratus than in S. trutta, thickening with age in both species. Numerous secretory goblet cells and sporadic secretory sacciform cells were observed in the upper and middle part of the epidermis in both species. Melanophores were present in both species only in the dermis, and were bigger in S. marmoratus and present at lower average density than in S. trutta, and more or less constant across all age classes. In adult S. marmoratus with fully established marble pigmentation, light areas at low density with small (i.e. aggregated) melanophores were present, while in S. trutta melanophores were more uniformly distributed.

Skin swabbing as a new efficient DNA sampling technique in amphibians, and 14 new microsatellite markers in the alpine newt (Ichthyosaura alpestris)

This study introduces a novel DNA sampling method in amphibians using skin swabs. We assessed the relevancy of skin swabs relevancy for genetic studies by amplifying a set of 17 microsatellite markers in the alpine newt Ichthyosaura alpestris, including 14 new polymorphic loci, and a set of 11 microsatellite markers in Hyla arborea, from DNA collected with buccal swabs (the standard swab method), dorsal skin swabs and ventral skin swabs. We tested for quality and quantity of collected DNA with each method by comparing electrophoresis migration patterns. The consistency between genotypes obtained from skin swabs and buccal swabs was assessed. Dorsal swabs performed better than ventral swabs in both species, possibly due to differences in skin structure. Skin swabbing proved to be a useful alternative to buccal swabbing for small or vulnerable animals: by drastically limiting handling, this method may improve the trade-off between the scientific value of collected data, individual welfare and species conservation. In addition, the 14 new polymorphic microsatellites for the alpine newt will increase the power of genetic studies in this species. In four populations from France (n=19-25), the number of alleles per locus varied from 2 to 16 and expected heterozygosities ranged from 0.04 to 0.91. Presence of null alleles was detected in two markers and two pairs displayed gametic disequilibrium. No locus appeared to be sex-linked.

Skin and Anti-Aging Research Update: Proceedings from the 2007 World Congress of Dermatology

Differences in how populations across the globe experience skin health and disease are affected by myriad factors. Demographics, genetics, immunology, environmental exposures, cultural practices, and the indigenous plants in a region will all affect population-based skin care and, ultimately, many aspects of appearance, including pigmentation and aging. Our understanding in all of these areas is increasing, but in some areas the data gaps remain large. On a population basis, there is little data available about the prevalence of skin conditions and practices worldwide. Moreover, we are just beginning to be able to quantify, characterize, and measure differences in skin structure and function that occur in what we perceive as normal skin. Areas with substantial progress include new imaging technologies, the identification of key genes involved in pigmentation, and an understanding of how the immune system responds to injury, including exposure to ultraviolet light. The use of new approaches that range from sophisticated and highly engineered technologies to the scientific evaluation of naturally found botanicals has paved the way for improvements in the formulations of skin care products that address the common problems of disordered pigmentation and photoaging.

Skin Differences, Needs, and Disorders across Global Populations

Accurately determining the incidence and prevalence of dermatologic disease in most large populations has been challenging for reasons ranging from the lack of easily quantifiable tests and measures to imprecision around definitions of race, ethnicity, photo skin type, pigmentation, and population groups. Compounding the problems with these categorizations is the fact that skin disease and skin health are affected not just by inherent risk factors but also by habits and environment. Thus, a fundamental question remains as we evaluate the effects of cultural and environmental factors: do genetic factors account for most of the difference that we see in skin types? Is the primary influence the way the skin mediates the environmental insult of UV radiation or how inflammation is handled? Is melanization the primary characteristic that we should measure and consider? This article will provide an introduction to current knowledge and future directions researchers are taking in differentiating both the biological differences of skin and the clinical manifestations of skin disease among the groups described above. This discussion will be followed by a brief overview of cultural practices and environmental factors that are known to have significant impact on skin disease and a summary of the most common conditions that are encountered worldwide.

Ethnic skin types: are there differences in skin structure and function?1

People of skin of colour comprise the majority of the world's population and Asian subjects comprise more than half of the total population of the earth. Even so, the literature on the characteristics of the subjects with skin of colour is limited. Several groups over the past decades have attempted to decipher the underlying differences in skin structure and function in different ethnic skin types. However, most of these studies have been of small scale and in some studies interindividual differences in skin quality overwhelm any racial differences. There has been a recent call for more studies to address genetic together with phenotypic differences among different racial groups and in this respect several large-scale studies have been conducted recently. The most obvious ethnic skin difference relates to skin colour which is dominated by the presence of melanin. The photoprotection derived from this polymer influences the rate of the skin aging changes between the different racial groups. However, all racial groups are eventually subjected to the photoaging process. Generally Caucasians have an earlier onset and greater skin wrinkling and sagging signs than other skin types and in general increased pigmentary problems are seen in skin of colour although one large study reported that East Asians living in the U.S.A. had the least pigment spots. Induction of a hyperpigmentary response is thought to be through signaling by the protease-activated receptor-2 which together with its activating protease is increased in the epidermis of subjects with skin of colour. Changes in skin biophysical properties with age demonstrate that the more darkly pigmented subjects retaining younger skin properties compared with the more lightly pigmented groups. However, despite having a more compact stratum corneum (SC) there are conflicting reports on barrier function in these subjects. Nevertheless, upon a chemical or mechanical challenge the SC barrier function is reported to be stronger in subjects with darker skin despite having the reported lowest ceramide levels. One has to remember that barrier function relates to the total architecture of the SC and not just its lipid levels. Asian skin is reported to possess a similar basal transepidermal water loss (TEWL) to Caucasian skin and similar ceramide levels but upon mechanical challenge it has the weakest barrier function. Differences in intercellular cohesion are obviously apparent. In contrast reduced SC natural moisturizing factor levels have been reported compared with Caucasian and African American skin. These differences will contribute to differences in desquamation but few data are available. One recent study has shown reduced epidermal Cathepsin L2 levels in darker skin types which if also occurs in the SC could contribute to the known skin ashing problems these subjects experience. In very general terms as the desquamatory enzymes are extruded with the lamellar granules subjects with lowered SC lipid levels are expected to have lowered desquamatory enzyme levels. Increased pores size, sebum secretion and skin surface microflora occur in Negroid subjects. Equally increased mast cell granule size occurs in these subjects. The frequency of skin sensitivity is quite similar across different racial groups but the stimuli for its induction shows subtle differences. Nevertheless, several studies indicate that Asian skin maybe more sensitive to exogenous chemicals probably due to a thinner SC and higher eccrine gland density. In conclusion, we know more of the biophysical and somatosensory characteristics of ethnic skin types but clearly, there is still more to learn and especially about the inherent underlying biological differences in ethnic skin types.

Population differences in skin structure and physiology and the susceptibility to irritant and allergic contact dermatitis: implications for skin safety testing and risk assessment.

Skin safety testing and risk assessment utilize a comparative toxicological approach whereby the inherent toxicity (irritation or sensitization) is related to exposure to determine the potential risk to a consumer population. However, consumers cover a broad spectrum of individual characteristics in terms of skin types and functions, as well as their basic habits and practices in use of consumer products. Thus, we try to use very conservative estimates for both inherent susceptibility to the toxic effect as well as the potential worst‐case exposures. While the inherent variation can be considerable even within a country, it is magnified even further when products are marketed globally. Questions have arisen, therefore, as to whether a skin safety testing approach conducted locally or regionally can adequately predict for adverse effects for the global consumer. A good deal of speculation exists that population differences are real and should mandate population‐specific safety testing prior to marketing products in certain regions of the world. In an attempt to address this question, this review has summarized extensive literature covering basic skin biology and function and susceptibility to irritant and allergic skin responses. Throughout this literature, there are individual studies demonstrating population differences in skin properties or in the responsiveness to chemical insult. Some of the research on this topic has pointed fairly convincingly to a demonstrable population difference. The best example of this is the tendency for blacks to have a lesser skin reactivity than Caucasians, likely due to a more impenetrable barrier. In contrast, the comparative data for Caucasians and Asians, for males and females, and for different age clusters are far less compelling. In terms of tendencies, there are little data to support any real difference in skin barrier function or in skin irritation responsiveness between Caucasians and Asians or between males and females. Comparing different age profiles, there does appear to be a slight decline in reactivity to irritants among the elderly (&gt; 65 years). Susceptibility to skin sensitization tends to be more related to exposure than any inherent susceptibility, though some data exist to suggest a slightly increased sensitivity in females versus males. On the basis of these data, standard procedures for skin safety testing and risk assessment can be considered relatively conservative. Most clinical skin safety studies are conducted in test populations that are comprised primarily of female Caucasians between the ages of 18 and 65 years. If anything, the skin reactivity “character” of this population cohort tends to skew toward the more reactive. This is not to say that population‐specific safety testing should not be done. There may be important reasons to pursue a population‐specific testing strategy in certain situations, perhaps due to regional, sex‐specific, or age‐specific marketing or to satisfy a regulatory or external relations need. However, there is yet no scientific justification to mandate such a strategy, based on our current knowledge of skin responsiveness and how it compares across diverse populations. There are clearly gaps in our understanding of population differences, particularly in regard to skin irritation that should guide future clinical research efforts. Side‐by‐side population testing for both acute and chronic skin irritation, more comparative testing of Asian subpopulations, testing for neurosensory irritation, and testing objective skin responses among hyperreactive subpopulations of multiple races are all areas in which additional research is needed. While current testing strategies have provided an excellent track record of success in providing safe and effective products to the world's consumers, results of such research will, in the future, help us to refine and further improve our skin testing and risk assessment capabilities.

Additive concentrates

A new frontier in the administration of therapeutic drugs to veterinary species is transdermal drug delivery. The primary challenge in developing these systems is rooted in the wide differences in skin structure and function seen in species ranging from cats to cows. The efficacy of a transdermal system is primarily dependent upon the barrier properties of the targeted species skin, as well as the ratio of the area of the transdermal patch to the species total body mass needed to achieve effective systemic drug concentrations. A drug must have sufficient lipid solubility to traverse the epidermal barrier to be considered for delivery for this route. A number of insecticides have been developed in liquid ‘pour-on’ formulations that illustrate the efficacy of this route of administration for veterinary species. The human transdermal fentanyl patch has been successfully used in cats and dogs for post-operative analgesia. The future development of transdermal drug delivery systems for veterinary species will be drug and species specific. With efficient experimental designs and available transdermal patch technology, there are no obvious hurdles to the development of effective systems in many veterinary species.

Colour dosing units

A new frontier in the administration of therapeutic drugs to veterinary species is transdermal drug delivery. The primary challenge in developing these systems is rooted in the wide differences in skin structure and function seen in species ranging from cats to cows. The efficacy of a transdermal system is primarily dependent upon the barrier properties of the targeted species skin, as well as the ratio of the area of the transdermal patch to the species total body mass needed to achieve effective systemic drug concentrations. A drug must have sufficient lipid solubility to traverse the epidermal barrier to be considered for delivery for this route. A number of insecticides have been developed in liquid ‘pour-on’ formulations that illustrate the efficacy of this route of administration for veterinary species. The human transdermal fentanyl patch has been successfully used in cats and dogs for post-operative analgesia. The future development of transdermal drug delivery systems for veterinary species will be drug and species specific. With efficient experimental designs and available transdermal patch technology, there are no obvious hurdles to the development of effective systems in many veterinary species.

The Influence of Skin Structure on Permeability: An Intersite and Interspecies Comparison with Hydrophilic Penetrants

For reasons that are unclear, skin from various body sites has different permeability properties. We have used hydrophilic penetrants (water, ethanol, mannitol, and paraquat) to study the in vitro permeability of skin from marmoset (eight body sites), man, and rat. Skin structure (stratum corneum thickness and number of cell layers; epidermal and dermal thickness; number and area of hair follicle openings per mm2) was compared with permeability. There was no apparent relationship between skin structure and permeability to the most rapid penetrants, water and ethanol. Follicle area opening was the structural feature that varied most between species and between body sites. Different marmoset body sites showed a threefold range in follicle area but this did not appear to influence the absorption rates of the test penetrants. However, among the species there was an 80-times range in follicle area, which correlated with the observed differences in rate of mannitol and paraquat absorption. Thus, permeability could be related to inter-species differences in skin structure, but only with the relatively slowly absorbed test penetrants, mannitol and paraquat.

New colour company in UK

A new frontier in the administration of therapeutic drugs to veterinary species is transdermal drug delivery. The primary challenge in developing these systems is rooted in the wide differences in skin structure and function seen in species ranging from cats to cows. The efficacy of a transdermal system is primarily dependent upon the barrier properties of the targeted species skin, as well as the ratio of the area of the transdermal patch to the species total body mass needed to achieve effective systemic drug concentrations. A drug must have sufficient lipid solubility to traverse the epidermal barrier to be considered for delivery for this route. A number of insecticides have been developed in liquid ‘pour-on’ formulations that illustrate the efficacy of this route of administration for veterinary species. The human transdermal fentanyl patch has been successfully used in cats and dogs for post-operative analgesia. The future development of transdermal drug delivery systems for veterinary species will be drug and species specific. With efficient experimental designs and available transdermal patch technology, there are no obvious hurdles to the development of effective systems in many veterinary species.