What Is Hair Loss?
Most people routinely lose between 70 and 150 hairs from their scalp each day, mainly through washing, brushing, and combing.
Scalp hair starts to thin when more hairs are lost through normal shedding than the scalp is able to renew. About 40% of the density of scalp hair has to be lost before thinning of the hair becomes noticeable.
Hair loss can be caused by:
- Heredity. Most balding is caused by a genetic predisposition - in other words, it's part of a person's genetic makeup. This is called male pattern baldness, or hereditary balding or thinning. It is the most common cause of thinning hair.
- Illness, certain physical conditions, or their treatments. This can include high fever, thyroid disease, childbirth, inadequate protein in the diet, iron deficiency, cancer treatments, the use of certain medications, and other causes.
Hair may be lost in two ways:
- In patchy hair loss, well-defined areas of hair are lost while the remaining scalp retains a good covering of hair.
- In generalized hair loss, there is a uniform thinning over the entire scalp with no areas of normal hair growth.
The medical term for hair loss is 
-
Alopecia areata is a disease in which well-defined bald patches occur. It usually clears completely within 6 to 12 months without treatment. - Alopecia totalis is an uncommon condition in which all hair on the scalp is lost. The cause is unknown, and the baldness is usually permanent.
- Alopecia universalis is a total loss of hair on all parts of the body.
- Androgenetic alopecia is balding caused by heredity. It can affect both men and women, although women with this inherited tendency do not become totally bald. The condition can start in a person's teens, twenties, or thirties.
| Nice To Know: The story of Samson and Delilah illustrates how, in the popular imagination, strength and virility have long been associated with an exuberant growth of hair - Samson's source of strength was his hair, which Delilah had shaved in betrayal of him. Indeed, many societies have shaved the scalp as a form of punishment. Today, however, more men are feeling comfortable with baldness. More celebrities and athletes are sporting bald heads, helping to dispel the myth that youth or masculinity are linked to a full head of hair. |
Every hair grows within a
If you pluck a hair and hold it up to the light, the root will appear as a bulbous white swelling at the deep end. The root lies between 2 and 4 millimeters (about a tenth of an inch) under the skin surface. Its purpose is to produce the actual hair, which is known technically as the
The hair shaft contains no living tissue. It consists of protein material twisted into a very fine rope-like arrangement. It is this part of the structure that we think of in everyday terms as "hair."
Each hair has:
- A
sebaceous gland , which provides fats and greases to the hair - An
erector muscle , which is responsible for lifting the hair off the surface of the skin at times of stress or to conserve warmth
The hair root does not grow continuously, but rather in a cycle of stops and starts.
- There is an initial period of active growth that lasts about three years.
- As the period of growth ends, the deepest part of the hair follicle wastes away.
- The hair root then enters a resting period of about 90 days, during which no further hair is produced by the resting root.
- At the end of this phase, the hair falls out and a new hair is produced.
Human hairs are randomly distributed all over the scalp in terms of their growth pattern, so that at any one time, some hairs will be actively growing while others are resting. Only those hairs ending their resting phase are lost each day.
There is tremendous variation in the number of hairs that people shed each day, depending on the number of scalp hairs and the length of the growth cycle. As people age, their rate of new hair growth slows down, resulting in a gradual thinning.
| Need To Know: Q: What should I do if I think I'm losing more hair than normal? A: If you notice you are shedding hair excessively after combing or brushing, or if your hair is becoming thinner, you should consult with your primary care provider or a dermatologist (a physician who specializes in treating skin and hair problems). A doctor can determine if disease is present and whether or not the hair loss will respond to medical treatment. |
| Facts About Hair And Hair Loss
|
What Causes Hair Loss?
The causes of hair loss vary, depending on the type:
- Generalized hair loss
- Patchy hair loss
- Balding in men
Abnormal hair loss may occur:
- Following certain illnesses and infections
- After prolonged vitamin deficiencies, or a deficiency of protein or iron
- Because of a disorder of the thyroid gland, in which there is too little thyroid hormone circulating throughout the body, causing inadequate stimulation of activity in body cells
- As a side effect of medication or medical treatment (for example, chemotherapy or radiation therapy for cancer)
- Following exposure to some toxic substances such as thallium (thallium sulfate is widely used as a rat poison)
In these cases, the hair loss is not immediately obvious. Although growth stops at once in the hair follicles, the dead hairs are not shed from the scalp until about three months later, when they fall out from their roots.
Major illness, injury, high fever, major surgery, severe bleeding, and possibly even severe emotional stress may cause sufficient physical upset to shock the actively growing hair roots into the resting phase, possibly to conserve energy that will be needed by the body for physical repair.
The roots remain securely anchored for three months, so there is no immediate apparent effect on hair growth following the illness or injury. But three months later, the hair sheds, and this may continue for some weeks.
Since this process does not damage the hair roots, they start to regrow - but it might be several weeks or months before new hair becomes apparent. Scalp hair grows at a rate of about 1 centimeter (around half an inch) per month.
| Need To Know: Cancer Treatments and Hair Loss Anticancer treatments are designed to destroy rapidly growing cells, whether by chemotherapy drugs or with radiation. The hair root consists of extremely active cells, which during the active growth phase are growing and multiplying briskly to produce new hair cells. Hair cells are very susceptible to anticancer treatments, targeted as these are against the most actively growing cells in the body. Fortunately, there is rarely any permanent damage. Hair growth usually returns to normal after therapy is completed. |
Patchy hair loss can be caused by:
-
Ringworm . Small patches of hair loss associated with dandruff-like scaling of the scalp and stubby, broken hair shafts within the bald area is typical of scalp ringworm. It occurs in children and is highly contagious, but it is not a serious threat to health. Once the diagnosis is made, the condition is easily treated with anti-ringworm treatment. -
Alopecia areata . This condition involves patchy hair loss with normal underlying skin; the cause is unknown. As the hair in one patch starts to grow again, another bald patch may develop elsewhere. No cure for this condition is known, but it usually clears up by itself in six months to a year.
| Need To Know: In alopecia areata, it is rare for all scalp hair to be permanently lost. But this is more likely:
|
Balding is a normal process that develops to some degree in all men. It is influenced by male sex
There also is a strong inherited factor in balding. The trait can be inherited from either the mother's or the father's side of the family. It can affect both men and women, although women with this inherited tendency do not become completely bald.
The process of balding is due to progressive miniaturization of individual hair follicles, which become smaller and have a shorter growth cycle. The hairs consequently become smaller and narrower. The number of hair follicles remains the same, however. There is the same number of hair follicles in the scalp of a bald man as in the scalp of a man with a full head of hair.
The very first signs of the effects of androgens on scalp hair growth occur soon after puberty, which is the stage in the human life when the reproductive organs reach maturity. In boys, puberty occurs around age 13. After puberty, the front hairline above the temples may recede. In some men, this may be as far as the balding process will develop.
There is tremendous variation in the extent to which individuals may lose hair.
- Some men experience a recession of the front hairline above the temples while retaining hair in the middle, which creates an "M" shape in the hairline above the temples and forehead.
- Some lose hair on the center of the scalp, which produces a "bald spot" surrounded by hair.
- Others have the recession at the front of their scalp join up with this area to create a larger balding area.
- Some develop uniform thinning of the hair over the top of the scalp, with no discernible pattern; this usually progresses to complete baldness.
| Nice To Know: In men who will become completely bald, the majority will lose their hair at a young age and will complete the balding process by their mid-thirties. |
No comments:
Post a Comment