Tuesday, June 11, 2013
FEATURED: Healthy Aging: A Lifelong Guide to Your Well- Being
In addition to being aesthetically unpleasing to some, many people complain that grey hairs are more cosmetically difficult to manage. Recent research using hair sample analysis supports this complaint by showing that grey hairs are indeed drier and less manageable with different mechanical properties and higher moisture loss than normally colored hair.
Hair greying is caused by a decrease in melaoncytes in the hair, which are cells that produce a natural pigment known as melanin. There is a myth that in 50% of the population, 50% of the hair will turn grey by age 50. This is known as the 50-50-50 rule of thumb. The problem is that this particular rule of thumb is not true. In a recent study of over 4000 healthy people, 6 to 23% of people (depending on geographic location) had at least 50% of their hair turn grey by age 50. What is true and is found repeatedly in the scientific literature is that Caucasian people’s hair turns grey earlier than that of Asians and African-Americans. Common causes of grey hair include smoking, stress, and genetic predispositions.
Some young people only have a specific hair turn grey while the others are normal color. This is known as acquired ciliary circumscribed grey-hair and has been found to be associated with a high degree of sulfur (a chemical element) and structural differences compared to normal hair.
Contrary to what many people believe, grey or white hair does not only happen in older people. For example, it is known to happen in an extremely rare condition known as progeria (click for a picture), in which the signs of old age are present before they should be -- when the person is a young child. There are other rare conditions in which silvery hair can occur in children. One example is Griscelli syndrome, a form of immunodeficiency (weak immune system) in which there is not enough pigment in the body.
Another rare immunodeficiency syndrome, known as Chediak-Higashi syndrome also presents with silvery hair (or silvery blonde hair) in children due to not enough pigment present. These syndromes are sometimes referred to as silvery grey hair syndrome. Differentiating between the two syndrome partly requires a microscopic analysis of the hair and skin. There is also a condition known as adult progeria (Werner’s syndrome) which is a genetic disorder characterized by premature graying (e.g., grey hair since the early 20s).
The medication, Tamoxifen, has been known to occasionally cause hair to turn from grey to a repigmented color by stimulating the production of melanin. Tamoxifen is a medication that is often used to treat breast cancer because it blocks the receptor for estrogen that come breast cancer cells require to grow. When tamoxifen undergoes metabolism, a substance is derived known as 4-hydroxy-tamoxifen, which also promotes the stimulation of melanin. Another medication, known as Clofazimine, which is used to treat leprosy, is also known to repigment the skin, because it contains a red dye and is slowly excreted by the body.
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Matamá T, Araújo R, Preto A, Cavaco-Paulo A, Gomes AC. (2013). In vitro induction of melanin synthesis and extrusion by tamoxifen. Int J Cosmet Sci. (in press).
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Yamamoto K, Imakiire A, Miyagawa N, Kasahara T. (2003). A report of two cases of Werner's syndrome and review of the literature. J Orthop Surg (Hong Kong). 11(2):224-33.
Posted by MedFriendly at 12:10 AM