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Leerunyakul K, Suchonwanit P. Asian Hair: A Review of Structures, Properties, and Distinctive Disorders. Clin Cosmet Investig Dermatol 2020; 13:309-318. [PMID: 32425573 PMCID: PMC7187942 DOI: 10.2147/ccid.s247390] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 04/08/2020] [Indexed: 11/23/2022]
Abstract
Asian hair is known for its straightness, dark pigmentation, and large diameter. The cuticle layer in Asians is thicker with more compact cuticle cells than that in Caucasians. Asian hair generally exhibits the strongest mechanical properties, and its cross-sectional area is determined greatly by genetic variations, particularly from the ectodysplasin A receptor gene. However, knowledge on Asian hair remains unclear with limited studies. This article aimed to review and summarize the characteristics and properties of Asian hair. It also aimed to discuss hair disorders including linear lupus panniculitis and pseudocyst of the scalp that occur distinctively in Asian populations.
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Affiliation(s)
- Kanchana Leerunyakul
- Division of Dermatology, Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
| | - Poonkiat Suchonwanit
- Division of Dermatology, Department of Medicine, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand
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Affiliation(s)
| | - Sarah L Stein
- Section of Dermatology, Department of Medicine and Pediatrics, University of Chicago Pritzker School of Medicine, Chicago, Illinois, USA.
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Rizer RL, Stephens TJ, Herndon JH, Sperber BR, Murphy J, Ablon GR. A Marine Protein-based Dietary Supplement for Subclinical Hair Thinning/Loss: Results of a Multisite, Double-blind, Placebo-controlled Clinical Trial. Int J Trichology 2016; 7:156-66. [PMID: 26903744 PMCID: PMC4738482 DOI: 10.4103/0974-7753.171573] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Introduction: Since skin and hair quality are potent vitality signals, and hair growth deficiency can cause significant psychological morbidity. In addition to clearly-defined hair loss disorders, milder forms of hair thinning or hair loss appear to be increasingly common, with a suggestion that sub-optimal diets and stressful lifestyles may be involved. Methods: Here we assess the value of a dietary marine-extract based dietary supplement in premenopausal women with subclinical hair thinning or hair loss conditions. This multi-site, randomized double-blind, placebo-controlled clinical trial was conducted with impact on hair shedding rate and hair fiber diameter (assessed by phototrichogram) as primary end points upon consumption of the oral supplement compared to a placebo. A total of 96 eligible female subjects were enrolled aged 21–55 years of age from Asian, Caucasian, and Hispanic ethnic backgrounds. Results: This study showed that hair shedding was significantly reduced in the first 3–6 months of daily consumption of the oral supplement. Moreover, phototrichogram image analysis revealed a statistically significant increase in the mean vellus-like hair diameter after 6 months of supplement consumption, when compared to the mean vellus-like hair diameters measured at baseline. Discussion: These results support the view that a nutritional supplement approach may be useful for women in this age group to deal with subclinical hair thinning or hair loss conditions, and those components of this marine extract-based oral supplement may be a useful adjunct.
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Affiliation(s)
- Ronald L Rizer
- Thomas J Stephens and Associates Inc., Colorado Research Center, Colorado Springs, CO, USA
| | - Thomas J Stephens
- Thomas J Stephens and Associates Inc., Texas Research Center, Richardson, TX, USA
| | - James H Herndon
- Thomas J Stephens and Associates Inc., Texas Research Center, Richardson, TX, USA
| | - Brian R Sperber
- Thomas J Stephens and Associates Inc., Colorado Research Center, Colorado Springs, CO, USA
| | | | - Glynis R Ablon
- Department of Dermatology, UCLA School of Medicine, Los Angeles, CA, USA
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Lewallen R, Francis S, Fisher B, Richards J, Li J, Dawson T, Swett K, McMichael A. Hair care practices and structural evaluation of scalp and hair shaft parameters in African American and Caucasian women. J Cosmet Dermatol 2015; 14:216-23. [PMID: 26300276 DOI: 10.1111/jocd.12157] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/07/2015] [Indexed: 11/30/2022]
Abstract
How African American hair fragility relates to hair care practices and biologic differences between races is not well understood. To assess the differences between perceptions of hair health, hair care practices, and several biologic hair parameters between Caucasian and African American women. A questionnaire on perceptions of hair health and hair care practices was administered. Biological and structural parameters of hair shaft and scalp, including growth, density, diameter, cycle, breakage, and scalp blood flow were also assessed in this case-control study. Significant differences between the Caucasian and African American women were observed in the questionnaire and biologic study data. Regarding self-reported perceptions of hair health, there were differences in the following: hair shaft type (P < 0.001), hair breakage (P = 0.040), and desire to change hair (P = 0.001). Regarding self-reported hair care practices, there were differences in the following: location of haircutting (P = 0.002) and washing (P = 0.010), washing frequency (P < 0.001), chemical relaxer use (P < 0.001), hooded hair dryer use (P < 0.001), and hair shaft conditioner use (P = 0.005). The two groups had similar practices in regard to the use of hair color, frequency of hair color use, chemical curling agents, and handheld blow dryer use. Regarding biological and structural parameters, there were differences in the following: hair growth rate (P < 0.001), density (P = 0.0016), diameter (P = 0.01), number of broken hairs (P < 0.001), and blood flow (P = 0.03). There was no significant difference in hair cycle parameters.The differences in hair care practices and hair fiber morphology among African American women may contribute to clinically observed variation in hair fragility and growth.
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Affiliation(s)
- Robin Lewallen
- Departments of Dermatology, Center for Dermatology Research, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
| | - Shani Francis
- Division of Dermatology, Pritzker School of Medicine, NorthShore University HealthSystem and University of Chicago, Chicago, Illinois, USA
| | - Brian Fisher
- Procter & Gamble Company, Mason Business Center, Mason, Ohio, USA
| | | | - Jim Li
- Procter & Gamble Company, Sharon Woods Innovation Center, Cincinnati, Ohio, USA
| | - Tom Dawson
- Institute of Medical Biology, Agency for Science, Technology, and Research (A*STAR), Singapore, Singapore
| | - Katrina Swett
- Department of Biostatistical Sciences; Division of Public Health Sciences, Winston-Salem, North Carolina, USA
| | - Amy McMichael
- Departments of Dermatology, Center for Dermatology Research, Wake Forest School of Medicine, Winston-Salem, North Carolina, USA
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Thibaut S, Gaillard O, Bouhanna P, Cannell DW, Bernard BA. Human hair shape is programmed from the bulb. Br J Dermatol 2005; 152:632-8. [PMID: 15840091 DOI: 10.1111/j.1365-2133.2005.06521.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
BACKGROUND Few biological data on curly hair follicles have been reported in the literature. OBJECTIVES To investigate the growth and morphology of curly hair follicles. METHODS Follicles were dissected from scalp skin samples from African, Guyanese and caucasian volunteers and were observed macroscopically, in culture in William's E medium, and by immunohistochemistry. RESULTS Macroscopic study of scalp biopsies obtained from African volunteers showed that the dermal implantation of follicles was curved with a retrocurvature at the level of the bulb, as opposed to a straight shape in caucasian follicles. The bulb itself was bent, in the shape of a golf club, while both the outer root sheath (ORS) and the connective tissue sheath were dissymmetrical along the follicle. In vitro growth of curly hair follicles was slightly slower than that of caucasian follicles but, more importantly, the curvature was maintained in the hair shaft produced in vitro. As shown by immunohistochemistry, the proliferative matrix compartment of curly hair follicles was asymmetrical, Ki-67-labelled cells being more numerous on the convex side and extending above the Auber line. On the convex part of the follicle, the ORS was thinner and the differentiation programmes of the inner root sheath and hair shaft were delayed. Furthermore, some ORS cells expressed alpha-smooth muscle actin protein on the concave side of the curvature, reflecting a mechanical stress. CONCLUSIONS Hair curliness is programmed from the bulb and is linked to asymmetry in differentiation programmes.
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Affiliation(s)
- S Thibaut
- L'OREAL Recherche, 14 rue Théodore de Banville, 75017 Paris, France
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Abstract
Differences have been found among blacks, whites, Asians, and Hispanics in various areas of skin structure and function. Among them is the stratum corneum lipid (ceramide) content, which is highest in Asians, then Hispanics, then whites, and lowest in blacks. Melanosomal packaging and percutaneous absorption rates for specific compounds also vary among the different races. Reports supporting the occurrence of difference in TEWL, tyrosinase levels, skin elasticity, and water absorption rates between blacks and whites, and reaction to skin irritation have been conflicting. No significant differences in corneocyte size, skin thickness, and skin biomechanics have been reported.
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Affiliation(s)
- Georgianna M Richards
- Department of Dermatology, Howard University College of Medicine, 2041 Georgia Avenue, NW, Washington, DC 20060, USA
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Abstract
The hair follicle is a unique composite organ, composed of epithelial and dermal compartments interacting with each other in a surprisingly autonomous way. This is a self-renewing organ that seems to be a true paradigm of epithelial and mesenchymal interactions. Each of the follicular compartments is endowed with a specific differentiation pathway under the control of an intricate network of growth factors, cytokines, and hormones. As observed for ethnic hairs, even the shape of the hair shaft is intrinsically programmed from the bulb.
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Taylor SC. Skin of color: biology, structure, function, and implications for dermatologic disease. J Am Acad Dermatol 2002; 46:S41-62. [PMID: 11807469 DOI: 10.1067/mjd.2002.120790] [Citation(s) in RCA: 208] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
People with skin of color constitute a wide range of racial and ethnic groups-including Africans, African Americans, African Caribbeans, Chinese and Japanese, Native American Navajo Indians, and certain groups of fair-skinned persons (eg, Indians, Pakistanis, Arabs), and Hispanics. It has been predicted that people with skin of color will constitute a majority of the United States and international populations in the 21st century. There is not a wealth of data on racial and ethnic differences in skin and hair structure, physiology, and function. What studies do exist involve small patient populations and often have methodologic flaws. Consequently, few definitive conclusions can be made. The literature does support a racial differential in epidermal melanin content and melanosome dispersion in people of color compared with fair-skinned persons. Other studies have demonstrated differences in hair structure and fibroblast size and structure between black and fair-skinned persons. These differences could at least in part account for the lower incidence of skin cancer in certain people of color compared with fair-skinned persons; a lower incidence and different presentation of photo aging; pigmentation disorders in people with skin of color; and a higher incidence of certain types of alopecia in Africans and African Americans compared with those of other ancestry. However, biologic or genetic factors are not the only ones impacting on these differences in dermatologic disorders. Cultural practices also can have a significant impact. Further studies are needed to help dermatologists optimally treat people with skin of color.
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Affiliation(s)
- Susan C Taylor
- Skin of Color Center, Department of Dermatology, St. Luke's-Roosevelt Hospital, New York, NY 10025, USA.
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Khumalo NP, Doe PT, Dawber RP, Ferguson DJ. What is normal black African hair? A light and scanning electron-microscopic study. J Am Acad Dermatol 2000; 43:814-20. [PMID: 11050586 DOI: 10.1067/mjd.2000.107958] [Citation(s) in RCA: 88] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
BACKGROUND The hair of normal black Africans forms a mat of tightly interwoven hair shafts. The effect of this on the structure of the hair shaft and the response to grooming is unknown. OBJECTIVE Our purpose was to use light and scanning electron microscopy (SEM) to examine the structure of Negroid-type hairs and effects of combing in black African volunteers. METHODS Hair samples were collected, by combing, from Africans and compared with those from Caucasian and Asian volunteers. The volunteers had never used chemical treatments. Their hair had not been cut for at least 1 year and grooming had been limited to shampooing, drying, and combing. RESULTS More than 2000 hairs in 12 African volunteers were examined by light microscopy. The hairs appear as a tight coiled springlike structure. Many shafts exhibited knots (10%-16% vs 0.15%) and appear broken compared with hair shafts from other ethnic groups. SEM of African hairs showed features consistent with repeated breaks of the shaft. Examination of hairs in situ showed interlocking of hair shafts. CONCLUSION These observations provide an understanding of the physical nature of, and effect of combing on, black African hair.
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Affiliation(s)
- N P Khumalo
- Department of Dermatology, The Churchill Hospital, University of Oxford, United Kingdom
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Hendriks WH, Tarttelin MF, Moughan PJ. Seasonal hair loss in adult domestic cats (Felis catus). J Anim Physiol Anim Nutr (Berl) 1998. [DOI: 10.1111/j.1439-0396.1998.tb00632.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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