Premature greying of hair
Premature greying of hair, also known as canities, can have a negative effects on appearance, confidence, self-esteem, and social acceptance of the affected individual. Hair is said to have greyed prematurely if it occurs before the age of 20 years in Whites, before 25 years in Asians, and before 30 years in Africans.
Cause of greying is incompletely understood. It is a complex multi-factorial process mainly considered to be an interplay of nutritional, genetic and environmental factors. Nutritional deficiencies like vitamin B12 deficiency, severe iron deficiency, chronic protein loss, copper deficiency are often found associated with premature greying of hairs. Other factors that have been incriminated are low serum ferritin, and low serum calcium and vitamin D3 levels.
Premature greying of hair has been observed with greater frequency among certain families, suggesting a familial predisposition for the condition. As hair pigmentation is a result of complex interaction between various genetic factors, it is thought that premature greying could be due to exhaustion of melanocyte's capability to produce hair pigmentation. Premature canities may occur alone as an autosomal dominant condition or in association with various autoimmune or premature aging syndromes. Down syndrome (trisomy 21) is characterized by features of accelerated aging including premature greying of hair and deficient DNA repair. Premature greying needs to be differentiated from various genetic hypomelanotic hair disorders.
Smoking is another factor that is considered to be related to premature greying of hair. Smoking results in generation of huge amount of reactive oxygen species leading to increased oxidative stress culminating into damage to melanin producing cells, melanocytes. Prolonged exposure to ultraviolet rays is considered to initiate similar processes in hair follicles resulting in premature greying of hair.
Topical antiaging compounds that are currently under investigation include photoprotectors, such as cinnamidopropyltrimonium chloride and solid lipid nanoparticles as carriers for UV blockers, oral supplementation with l-cystine and l-methionine, and topical melatonin. Temporary hair colorants are used worldwide.
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