Hair Loss General Questions
 

What causes hair loss?
Alopecia is the general medical term for hair loss, and it has many different causes. Normal human hairs can be classified according to their phases of growth. Anagen is the growing stage of hair, while telogen is the sleeping stage of hair. About 80 percent of the hairs in the human scalp are growing hairs and about 20 percent of them are sleeping hairs. It has been estimated that the scalp normally contains about 100,000 hairs. Therefore, the average number of hairs that can be lost in a day is about 100. Contrary to popular belief, neither shaving nor hormonal changes, such as menstruation, has any effect upon hair growth.

Hair loss can be broken down into several different types, including alopecia areata (temporary hair loss in a coin-shaped patch), telogen effluvium (temporary hair loss secondary to a stressor on the system), and androgenetic alopecia (male-pattern hair loss). For the purposes of our discussion, we will focus on male-pattern hair loss. It generally shows itself in the 20s or early 30s by gradual loss of hair, chiefly on the top of the head and in the angles at the frontal hairline. There are several different patterns to this hair loss, but male-pattern hair loss is the most frequently encountered type. The exact mechanisms are still unknown. We have no doubt, however, that inherited factors and the effect of androgens (male hormones) on the hair are most responsible.
 

Is stress a factor in hair loss?
Stress does not cause hair loss it simply makes a bad situation worse. Telogen effluvium, for example, occurs after an insult to the system. The most common cause is pregnancy. This can result in extensive and worrisome hair loss in women in the first few months after the birth of a baby. It is, however, temporary and returns completely.
 

What is DHT and how is it involved in hair loss?
DHT stands for dihydrotestosterone. This is the active form of the male hormone testosterone. It has been suggested that high DHT levels in genetically predisposed hair follicles initiate baldness. It is this chemical conversion from testosterone to dihydrotestosterone that is blocked by hair restoration products, such as finasteride, which is a prescription medicine and the active ingredient in Propecia, another prescription medication to treat hair loss. Finasteride blocks the formation of active testosterone and allows those hairs predisposed to inactivity to become active again and make new hairs.
 

What is the relationship between genetics and hair loss?
Although not the primary cause of male-pattern hair loss, genetics does have a significant role in male-pattern hair loss. It is, however, polygenic, in that there is more than one factor at work. It is unclear whether having an affected mother or an affected father predisposes descendants to greater risks.
 

Can hair loss occur in young adults?
Male-pattern hair loss can occur as early as 15, although it typically begins anywhere from the 20s and early 30s. Familial history may help determine if this is going to occur, as parents with a history of early-onset male-pattern hair loss may increase the risk for this to occur in descendants. Alopecia areata and telogen effluvium, two other forms of temporary hair loss, can occur in children as young as one year of age. Other precipitating factors may also be involved.
 

What can be the cause of a sudden loss of a large mass of hair?
Stressors to your system, such as illness, high fever, pregnancy, extreme weight loss or gain, and drug use, can cause temporary hair loss. This occurs when the ratio of growing to resting hairs is upset and more of the growing hair shifts into a resting phase. A greater quantity of normally sleeping hairs falls out, prompting a visit to the dermatologist. This type of hair loss is temporary and full regrowth should be expected.
 

Do shampoos and other hair products cause hair loss?
An allergic reaction to any constituent in shampoo or hair products can cause hair loss. Shampoos are designed to be as safe as possible, although there is always someone who will react to them. Caustic hair dyes, straighteners, and other products can certainly cause inflammation of the scalp and result in hair loss.
 

Can my hairstyle cause my hair to fall out?
Certain hairstyles can contribute to hair loss, most notably styles involving tight braids or pull-backs. This form of hair loss is called traction alopecia. This occurs when the hair is pulled tightly back and fastened at the base of the skull, or braided into tight braids or rows. Exposure to this type of hairstyle over long periods can result in a scarring alopecia, with no potential for regrowth.