CAUSES OF HAIR LOSS
Causes Of Hair Loss
One of the most common types of hair loss in both men and women is androgenetic alopecia, or the male-pattern baldness or female-pattern baldness. It is related to hormone levels in the body as well as a genetic tendency to lose hair, which may be inherited. It affects 50 per cent of men and as many women over the age of 40. The cause of hair loss is a body chemical called dihydro-testosterone (DHT) which is synthesized in the body from the male hormones (androgen’s), that all men and women have, by the action of the 5-alpha reductase enzyme. People having a lot of this enzyme make more DHT in their body, causing the hair follicles to make thinner and thinner hair until, eventually, they disappear completely.
In men, the loss of hair follows a semicircular pattern around their head, with the hair on the sides and back of the head left untouched. Women’s pattern of hair loss is different; it is a general thinning of women’s hair, with loss predominantly over the top and sides of the head.
Another important cause of hair loss is alopecia areata, an autoimmune disease where the hair follicles are attacked by white blood cells, making the follicles small and slowing hair production so dramatically that there may be no visible hair growth for months or years. This results in the development of patches of baldness, usually in small circular areas of the scalp. This disease usually affects young adults of both genders. After some time, hair may come back in patchy areas, or not re-grow at all. A severe form of alopecia areata is the total loss of scalp hair (alopecia totalis), the complete loss of all body hair (alopecia universalis). About 33% of those afflicted with these rare problems will grow back all their hair within a year. Recurrences may not occur at all.
Telogen Effluvium (Stress Trigger)
Another common form of hair loss is a condition called Telogen effluvium in which there is a widely spread out shedding of hair around the scalp and elsewhere on the body. This is usually a reaction to intense stress on the body’s physical or hormonal systems or as a reaction to medication. The condition can occur at any age. It generally begins suddenly and gets better on its own within six months, but for some people it can become a chronic problem. Telogen effluvium is a phenomenon related to the growth cycles of hair. Hair growth cycles alternate between a growth phase (called Anagen which lasts about three years) and a resting phase (Telogen which lasts about three months). During Telogen, the hair remains in the follicle until it is pushed out by the growth of a new hair in the Anagen phase. At any one time, up to about 15% of hairs are in Telogen. But three months later, this large number of hairs will be shed. However, as the new hairs start to grow out, the density of hair may thicken again.
Anagen Effluvium (Chemical Damage)
Like Telogen effluvium, this form of hair loss initially causes patchy loss of hair, which often then advances to total hair loss. In this form of hair loss, rather than just shutting down the hair follicle, a chemical actually kills the hair follicle and Anagen hair. The most common example of this are the effects of drugs used to treat cancer. The hair usually grows back within six months of the end of chemotherapy.