Anities, “Graying” as spelled by the Americans or “Greying” by the British, is usually a manifestation of ageing process. It is considered as a change in hair color that is associated with an older look and feel (Seiberg, 2017). Generally canities starts in the third to fourth decade of life, starting on the temples, spreading later to the crown and occiput. An inaccurate universally believed rule of thumb dating since the sixties (Panhard et al., 2012), estimates that 50% of the population will have at least 50% gray hair by the age of 50 years (Keogh and Walsh, 1965).
Premature hair graying has been defined by Tobin and Paus (2001) as graying that occurs in patients younger than 20 years of age, and appears …show more content…
As the age of onset of graying is dependent more on the genotype of individuals, it is subjected to racial variation. Average age of onset in Caucasians is 34±9.6 years, while it is 43.9±10.3 years in Negroes. On the other hand graying of hair appears from 30 to 34 years in Japanese men and from 35 to 39 years in Japanese women. As an average, Caucasians begin to have gray hair in their mid-thirties, Asians in their late thirties, while Africans start to have their hair gray latest in their mid-forties. In Bantus, graying of hair is said to be uncommon before 40-50 years of age (Pandhi and Khanna, 2013).
Graying is more apparent and noticed earlier in those with darker hair color, while individuals with fair hair appear totally gray earlier (Mosher et al., 2012). Although, Both sexes are equally affected, temporal and occipital areas are more commonly involved in men than in women, with graying usually starts in the temporal area in men while in the frontal area in women (Jo et al., …show more content…
Full range of color from normal to white can be seen both along individual hair and from hair to hair. The perception of hair color is affected by the physical characteristics of the hair shaft, and has a little relationship to the true colors of the shaft. The gray color is derived from an admixture of fully white and fully pigmented hair. Canities may affect individual hair follicles during a single anagen growth phase, such that there is a gradual loss of pigment along the same hair shaft, with increased reflection of light on cell interfaces and interfibrillary matrix (Pandhi and Khanna, 2013).
Gray hair undergoes more severe UV damage and needs extra UV protection than dark brown hair. Moreover, it is believed to be coarser, stiffer, and less manageable than pigmented hair (Choi et al.,