The Normativist Theory
Lawrie Reznek in The Nature of Disease, 1987
There is the following more serious objection. It might be argued that the condition of having black skin in a white racist society is something that makes those individuals worse off. But it would be wrong to say that the condition is a disease. We might try to avoid this by saying that the individual is not made worse off by his black skin but by the social prejudice acting on that trait. But individuals with albinism are also not made worse off by the fairness of their skins, but by the sun’s rays acting on that trait. And albinism is still a disease. Norman Daniels points this problem out: [W]e must specify the range of environments taken as ‘natural’ for the purpose of revealing dysfunction. The latter is critical to the second feature of the biomedical model: for example, what range of social roles and environments is included in the natural range? If we allow too much to the social environment, then racially discriminatory environments might make being of the wrong race a disease; if we disallow all socially created environments, then we seem not to be able to call dyslexia a disease (disability) (Daniel, 1981, p. 156).
Cutaneous Photosensitization
David W. Hobson in Dermal and Ocular Toxicology, 2020
The integument has certain intrinsic protective barriers to minimize damage from light exposure. Skin is an optically inhomogeneous medium that serves to modify the radiation that reaches deeper structures via the mechanisms of reflection, refraction, scattering, and absorption. The stratum corneum reflects 5 to 10% of incident solar radiation. In addition, the dead cells of the stratum corneum are composed primarily of keratin, a fibrous protein that absorbs significantly in the UVB and UVC spectral bands and also scatters most visible radiation because of its structural characteristics. The DNA present in these outer epidermal layers will absorb incident UV radiation allowing only 5 to 10% of solar radiation in the 290 to 310 nm band to actually penetrate to the basal epidermal cell layer and superficial dermal vasculature. However, wavelengths above 330 nm readily penetrate the epidermis to reach the deeper photosensitive dermal layers. In Caucasian skin, as much as 50% of incident UVA radiation may be transmitted to the basal cell layer and dermis. There is a significant reduction in UVA transmission in blacks, and those individuals with very dark skin may have as little as 5 to 10% of the incident UVA penetrate the epidermis. This phenomenon is due to the quantitative differences in the light-absorbing pigment, melanin, which serves to further protect the skin from light-induced damage. A more thorough review of these principles is available in other sources.1
Photochemotherapy
Henry W. Lim, Nicholas A. Soter in Clinical Photomedicine, 2018
Chronic exposure to PUVA therapy produces changes in the skin that resemble the premature aging changes due to sunlight. Early in the course of treatment the skin appears dry and wrinkled but this is reversible once treatment is stopped. Later in therapy there is freckling, telangiectases, and disturbance of melanization in the form of macules of hypopigmentation. These changes are only partially reversible (41–43). The development of photoaging is related to the total dose of treatment, being more marked at higher doses, and the intensity of treatment, so that a high doses over a short period is more likely to produce changes. Individual susceptibility varies; people with fair skin are more prone and those with dark skin are relatively immune to the changes.
Skin cancer awareness and sunscreen use among outpatients of a South African hospital: need for vigorous public education
Published in South African Family Practice, 2018
NC Dlova, R Gathers, J Tsoka-Gwegweni, RJ Hift
Understanding the link between sun exposure and skin damage, the protective effects of sunscreens against photo ageing, and the concept of the sun protection factor (SPF) was significantly poorer among black African respondents: just 11% reported frequent recreational sun exposure. This is likely to be culturally mediated rather than for reasons of health, a fairer (i.e. non-tanned) skin being pervasively and historically regarded as more attractive in females of both Asian and some African societies, particularly South Africa.20–26 It is known that there is a strong cultural propensity to prefer light skin rather than dark skin amongst our black African and Indian population, and that skin-bleaching practices are common in this population. Prevalence rates of skin bleaching in sub-Saharan Africa have been reported as between 26% and 67%, despite an array of potential adverse side effects from the practice.27 Though the desire for a lighter complexion might be expected to be a powerful driver for regular use of sunscreen, our respondents showed little understanding of sunscreen use in terms of SPF, the need for regular use in the black African population and its role in cosmesis. Female respondents were twice as likely to answer positively on these questions as males (p < 0.0001), a wider margin than was shown for the knowledge questions in general.
The “in’s and outs” of laser hair removal: a mini review
Published in Journal of Cosmetic and Laser Therapy, 2019
Mandy M. Thomas, Nicolette N. Houreld
Any light-based therapy relies on the absorption of the photons by specific chromophores (targets). In the skin, these chromophores can include tattoo ink, haemoglobin, melanin, water and collagen. In the case of laser hair removal, the chromophore is melanin located within the hair bulb and hair shaft. During laser hair removal, a high-intensity pulsed laser beam (or broad-spectrum light source in the case of IPL) is directed at the target. The emitted light is primarily absorbed by melanin in the hair, and converts the light energy into an intense heat energy that diffuses into and destroys the hair follicle. While stem cells located in the hair bulge do not contain melanin, they are also targeted and destroyed by thermal damage through the diffusion of the heat energy from the hair follicle (Figure 1) (6). This damage to the stem cells prevents future hair regrowth (7). In patients with dark skin, melanin located in the epidermis interferes with this mechanism of action. Epidermal melanin competes with melanin within the hair follicle, and the epidermis absorbs the photons. Thus, these patients experience poorer clinical outcomes and a higher rate of thermally induced adverse effects (7).
Prevalence of Vitamin D deficiency in a multiracial female population in KwaZulu-Natal province, South Africa
Published in South African Family Practice, 2019
Yeshnee Naidoo, Jagidesa Moodley, Lorna Madurai, Thajasvarie Naicker
In the < 18-year age group, 41.1% of the Indian participants had severe vitamin D deficiency and VDD levels with the mean age reported at 11.3 years old. Only 1.35% of the Black group was VDD whilst none was reported in the White group (Figure 2). However, when stratified by race, a limitation of the study was the small sample size of < 18-year age group. In the present study 41.1% of Indian children had 25(OH)D < 13 ng/ml, therefore there is a need to assess the 25(OH)D levels in South African children, with a focus on the Indian group. Nonetheless, it is well documented that vitamin D levels in children of Black race are associated with vitamin D deficiency, and dark skin is a risk factor for vitamin D deficiency.25,26 Despite previous studies showing that those of Black ethnicity have lower levels of vitamin D, the results in the present study were dissimilar.22,38 Interestingly, a study conducted by Poopedi et al. (2009)39 reported vitamin D deficiency among children in Johannesburg, SA. The latter study correlates with our study in that 74% of the Black population aged 10 years had adequate vitamin D status.
Related Knowledge Centers
- Evolution
- Perspiration
- Pyrimidine Dimer
- Skin Color
- Spermatogenesis
- Embryo
- Ultraviolet
- Melanin
- Light Skin
- Folate