Sunlight as a Factor Influencing the Thickness of Epidermis

Freeman, Robert G.; Cockerell, Earl G.; Armstrong, Jim; Knox, John M.

doi:10.1038/jid.1962.115

Cited by 66 publications

(18 citation statements)

References 4 publications

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“…2 and 3 is affected by experimental errors, variation between individuals and variation between individual body sites within the main body site grouping. This suggests that epidermal thickness is affected to some extent by environmental factors, and supports the observations of Freeman et al (1962) that sunlight affects the physical dimensions of the skin. Before grouping the results a preliminary check was made on whether there was any obvious difference between specific body sites within one of the main body site groups, such as comparison between the front and back of the wrists.…”

Section: Variation Of Epidermal Thickness Between Individualssupporting

confidence: 88%

The thickness of the epidermis

1973

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Epidermal thickness has been accurately measured on 214 samples of skin from 188 volunteers. Variations with the individual, body site, sex and age are described and discussed.An original technique of measurement has been developed which has several advantages over conventional methods. In particular, quick straight-forward measurements are possible on volunteer skin rather than post mortem material, and the method eliminates errors arising from the skin's elasticity.These improvements in accuracy have confirmed that much information in the literature on epidermal thickness, is misleading as the results are based on inaccurate techniques of measurement. * I mg/cm^ ^ 10 /*m in tissue. 467

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Section: Variation Of Epidermal Thickness Between Individualssupporting

confidence: 88%

The thickness of the epidermis

1973

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“…and stratum comeum (SC). Regarding SC thickness, chronological and photo-ageing changes (1,2), the relationships between epidermal thickness, pigmentation and human photosensitivity (3). and regional diUcrenccs (4.…”

mentioning

confidence: 99%

In vivo Estimation of Stratum Corneum Thickness from Water Concentration Profiles Obtained with Raman Spectroscopy

Egawa¹,

Hirao²,

Takahashi³

2007

Acta Derm Venereol

300

248

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Stratum corneum thickness was estimated from water concentration profiles of the skin measured by a confocal Raman spectrometer. Stratum corneum apparent thickness (SCAT) was defined as the depth where the water content reached an almost constant value. Site variations were determined using 15 healthy Japanese subjects (6 males, 9 females), and age variations at the cheek and forearm were examined using 27 female Japanese subjects. There were marked site variations in mean SCAT; 16.8 microm for cheek, 22.6 microm for volar forearm, 29.3 microm for back of the hand, and 173.0 microm for palm. These variations were similar to reported stratum corneum thickness values obtained in biopsy tissues. The SCAT tended to become age-dependently thicker at the forearm, but not at the cheek. In addition, SCAT was increased up to two-fold by hydration for 90 min, while lesser increases were seen with shorter hydration periods.

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“…Even though the stratum corneum is equally thick in black and white skin [2,3] , Weigland et al [4] demonstrated that the stratum corneum of the African-American population contains more cell layers. On average 20 cell layers were observed in African-Americans versus 16 layers in Whites.…”

Section: Introductionmentioning

confidence: 99%

Ethnic Variation in Vellus Hair Follicle Size and Distribution

Mangelsdorf

Otberg²,

Maibach³

et al. 2006

Skin Pharmacol Physiol

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It is a given fact that hair follicles play an important role in the penetration process of topically applied drugs and cosmetics. Since exact knowledge of the potential follicular reservoir is essential for understanding and calculating the penetration process, this knowledge may indeed help to optimize the development of topically applied drugs and cosmetic products. We know that variability in skin properties exists among the human population, but it is the deciphering and quantification of these differences that may help to explain racial disparities in dermatological disorders and provide a basic approach for treatment and prevention. Data pertaining to structural and functional differences within ethnic skin types (reviewed in this paper) support the assumption that hair follicles in the various skin types are not equal. Thus, the need to investigate follicular morphology in non-Caucasian skin types becomes more than apparent. The aim of the present study was to determine the potential reservoir of vellus hair follicles in non-Caucasian skin types in order to estimate their contribution to the penetration of topically applied substances. Cyanoacrylate skin surface biopsies were taken from seven body sites of Asians and African-Americans. To determine the follicular reservoir, the samples were evaluated under the light microscope. Follicular parameters were measured with the help of a digital imaging software program. In the evaluation and comparison of the results with those of Caucasians, significant differences were detected. Compared with Whites, follicular density on the forehead is significantly lower in Asians and African-Americans. Smaller values were detected for volume, surface, follicular orifice and hair shaft diameter on the thigh and in calf regions in Asians and African-Americans. Furthermore, the follicular reservoir, characterized by follicular volume, is generally higher in Caucasians. In comparison to African-Americans, larger follicular volumes on the forehead, back and on the upper arm were determined in Asians. The fairly similar density in these sites revealed that Asians have a higher follicular reservoir in these sites. Due to significant ethnic differences in the follicular reservoir, particularly on the calf and forehead, prospective skin absorption experiments need to be performed on different skin types in order to be representative. Likewise, the development of topically applied drugs should take place under adequate consideration of ethnic differences in skin physiology.

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Sunlight as a Factor Influencing the Thickness of Epidermis

Cited by 66 publications

References 4 publications

The thickness of the epidermis

The thickness of the epidermis

In vivo Estimation of Stratum Corneum Thickness from Water Concentration Profiles Obtained with Raman Spectroscopy

Ethnic Variation in Vellus Hair Follicle Size and Distribution

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