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Vitiligo
Published in Charles Theisler, Adjuvant Medical Care, 2023
Vitiligo is a cosmetic problem caused by the loss of cells (melanocytes) that produce skin color (melanin) resulting in white blotches on the skin. Often the patches begin on areas of skin that are exposed to the sun and effect both sides of the body. Vitiligo tends to expand over time, causing larger areas of skin to lose pigment. It may begin at any age, but the average age of onset is in the mid-twenties.1 Vitiligo is more common in people with autoim mune diseases. There is no cure for vitiligo, but available treatments may stop its progression and induce varying degrees of re-pigmentation. A combination of therapies is usually more effective than any single therapy.1
Disorders of Pigmentation
Published in Ayşe Serap Karadağ, Lawrence Charles Parish, Jordan V. Wang, Roxburgh's Common Skin Diseases, 2022
Michael Joseph Lavery, Charles Cathcart, Hasan Aksoy
Overview: Skin color is predominantly determined by the quantity or distribution of melanin. Hyperpigmentation is typically secondary to melanin overproduction but sometimes develops due to an increase in active melanocytes. Skin color changes may also occur via different mechanisms due to medications or heavy metals. Hyperpigmentation can be localized (e.g., melasma, nevus of Ota; Figure 25.4) or generalized (e.g. Addison disease) in distribution, and circumscribed, linear, or reticulate in configuration.
Cancer Biology and Genetics for Non-Biologists
Published in Trevor F. Cox, Medical Statistics for Cancer Studies, 2022
A gene can have different codings, and these variants are called alleles. One allele is inherited from your mother and one from your father for each gene, and these determine your physical traits (phenotype), such as hair colour, height, etc. The combination of the alleles that you have inherited make up your genotype, but we can also use this term for a particular gene. If there are two possible alleles for a gene, A and a, there are three possible genotypes, AA, Aa and aa, depending on which alleles you inherited. For example, the OCA2 gene on chromosome 15 is associated with melanin production, which is a pigment for hair, eye and skin colour. A might be the allele for brown eyes and a for blue eyes. A is dominant and a is recessive, and so individuals with AA and Aa will have brown eyes, and individuals with aa will have blue eyes. But eye colour is not quite so simple as this as other genes are also involved. The allele that codes for the most common phenotype is called the wild type allele.
Relationship between Fitzpatrick Skin Type and The Cancer Genome Atlas Classification with Melanoma-Related Metastasis and Death in 854 Patients at a Single Ocular Oncology Center
Published in Ophthalmic Genetics, 2022
Mrittika Sen, Kevin R. Card, G. Brandon Caudill, Nina R. Spitofsky, Philip W. Dockery, Alexandra R. Zaloga, Jennifer S. Zeiger, Charles F. DeYoung, Samara J. Hamou, Carol L. Shields
The Fitzpatrick skin type has been studied for dermatological conditions, particularly for cutaneous melanoma (16,27). Olsen et al conducted a systemic review and meta-analysis of 42 studies and quantified the relative risk for cutaneous melanoma to 2.27 for FST I, 1.99 for FST II, and 1.35 for FST III compared to FST IV (p < 0.001) (28). The relationship of FST with conjunctival melanoma was studied by Shields et al in 540 consecutive patients with FST II being the most common skin type (n = 337, 62%) (18). Patients with FST III-VI had younger age at presentation, thicker tumors and eyelid involvement but no difference in the 5-year rate of vision loss, tumor recurrence, exenteration, metastasis, or death based on the FST (18). This was consistent with an earlier study by Brouwer et al where skin color was not related to tumor pigmentation or outcomes in patients with conjunctival melanoma (29). Regarding uveal melanoma, Weis et al studied the relationship of host susceptibility factors and uveal melanoma and found a significant association between light skin color and the lack of ability to tan with the development of uveal melanoma (4). Seddon et al estimated the relative risk of developing uveal melanoma to be 3.8 in people of light skin color compared to dark skin color (8). The prognosis of uveal melanoma based on race has been shown to have no difference, but outcomes based on precise skin color has not been evaluated (6).
Metabolic Syndrome and Its Components are Linked with Increased Risk of Non-Melanoma Skin Cancers in Iranian Subjects: A Case-Control Study
Published in Nutrition and Cancer, 2022
Fatemeh Rezaiian, Sayed Hossein Davoodi, Bahareh Nikooyeh, Amir Houshang Ehsani, Ali Kalayi, Nastaran Shariatzadeh, Maliheh Zahedirad, Tirang R. Neyestani
Non-melanoma skin cancers (NMSC) are among the most prevalent malignancies globally (1). The incidence of skin cancers in Iran is escalating (2) comprising nearly 15% of all types of cancers (3). Light skin color, constitutional susceptibility (based on the skin color and type, natural hair color, childhood tendency to tan and the number of palpable moles on arms) and direct sun exposure are among the major risk factors for skin cancers (4). Indeed, ultra violet-B (UVB) has been known as the main causative factor for development of skin cancers (5). It has been estimated that UVB exposure is responsible for over 99% of NMSC cases, including about 99.8% of squamous cell carcinomas (SCC) and 99.4% of basal cell carcinomas (BCC) (6). As a result, avoidance of direct sun exposure is commonly recommended which may bring about the consequent vitamin D deficiency (7).
Vitamin D levels on sports injuries in outdoor and indoor athletes: a cross-sectional study
Published in The Physician and Sportsmedicine, 2022
Seçkin Şenışık, Ogün Köyağasıoğlu, Nevzad Denerel
It has been demonstrated in many studies that the level of vitamin D is higher in people who do outdoor sports than those who do indoor sports [13,29]. In our study, the level of vitamin D was higher in football players who did outdoor sports than those who did indoor sports such as basketball players and swimmers. Longer exposure to sunlight may explain higher vitamin D levels in outdoor athletes [30]. The difference in vitamin D levels among athletes despite doing sports in the same field may be due to the duration of exposure to UV rays or a decrease in the absorption of vitamin D as a result of some factors that reduce the effect of sun rays. Maroon et al. [31] found a vitamin D level of 27.4 ± 11.7 ng/mL in their study on American football players. This value is below the level which we have found in football players (32 ng/mL). While black athletes occupy the majority of the subjects in the study of Maroon et al., the participants in our study were all white. This difference is not surprising as dark skin color is a risk factor for vitamin D deficiency. Additionally, the fact that American football players are less exposed to ultraviolet rays depending on the sportswear and equipment they use, may explain this difference.