Time-Dependent Variations of the Skin Barrier Function in Humans: Transepidermal Water Loss, Stratum Corneum Hydration, Skin Surface pH, and Skin Temperature

Yosipovitch, Gil; Xiong, Glen L.; Haus, Erhard; Sackett-Lundeen, L; Ashkenazi, Israel; Maibach, Howard I.

doi:10.1046/j.1523-1747.1998.00069.x

Cited by 281 publications

(229 citation statements)

References 14 publications

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“…This has recently been exemplified by Choi et al [6]. Circadian rhythms also occur that influence, in particular, sweat and sebum secretions [7,8]. Naturally diet will have a big influence on skin composition and function [9].…”

Section: Introductionmentioning

confidence: 99%

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

Rawlings¹

2006

Intern J of Cosmetic Sci

324

277

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SynopsisPeople 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...

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Section: Introductionmentioning

confidence: 99%

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

Rawlings¹

2006

Intern J of Cosmetic Sci

324

277

View full text Add to dashboard Cite

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“…9 Peripheral circadian clocks have been found in virtually every mammalian cell and tissue, including the skin. 10 The circadian pattern of increased transepidermal water loss 11 and decreased cortisol secretion at night may promote itch during the time coinciding with sleep. Indeed, many cutaneous disorders are associated with itch that is exacerbated at night.…”

Section: Conclusi Onmentioning

confidence: 99%

Sleep Related Scratching: A Distinct Parasomnia?

Nigam

Riaz

Hershner

et al. 2016

Journal of Clinical Sleep Medicine

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Pruritus (itching) during the sleep period can present as a symptom of dermatological or systemic disease, or as a parasomnia. Sleep related scratching as a primary parasomnia, exclusively confined to sleep in the absence of coexisting dermatological disorders, has not been well described. This case series describes three such patients, and discusses potentially relevant pathophysiology that can underlie itching or pain. Such cases of sleep related scratching may merit nosologic classification apart from previously defined parasomnias.

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“…Because the acidity of the human skin surface varies within the pH range of about 4-6, the lipophilicity of HQ-2P2IS was investigated using an n-octanol/10 mM sodium acetate buffer pH 5.0 system at 37 Table 1 22 24 . The distribution percent of HQ-2P2IS was found to be 98.6 .…”

Section: Partition Of Hq-2p2is In N-octanol/buffer Systemsmentioning

confidence: 99%