Causes and Types
Diet for Good Hair
Other Permanent Baldness
Patchy Hair Loss
Traction Alopecia and Trichotillomania
Hair loss or baldness, scientifically known as alopecia, results when hair loss occurs at an abnormally high rate, replacement hair (new growth) fails to keep up with hair loss, or when normal hairs are replaced by thinner, shorter ones.
Everyone experiences some hair loss. This is because hair is shed naturally as part of the normal hair growth cycle. As each new hair prepares to grow out from the hair follicle, the old hair is pushed out and shed. Other types of shedding--sudden or excessive shedding--are caused by a host of factors, including disease, radiation damage, certain medications, and so on.
Androgens, or male hormone, have a major influence in regulating hair growth. As far back as 400 BC, Hippocrates observed that eunuchs did not become bald, indicating that a male-specific factor was involved in hair loss. Women tend to have less extensive hair loss or thinning hair than men, because women produce lower amounts of androgens which are the primary sex hormones produced in the testes.
Thinning of the hair, or alopecia, occurs in approximately 30-40% of adults, in both men and women. Hair loss is caused mainly by heredity and ageing, or a variety of other conditions. Other causes include thyroid disorders, inadequate protein intake, anaemia, circulatory problems, hormonal changes, deficient of vitamins A or B, poor nutrition, emotional or physical stress, ingestion of certain medications (such as oral contraceptives), and improper hair care. Medication such as cancer chemotherapy or radiation therapy administered to the head could also effect in hair loss. Hair loss from chemotherapy is temporary; hair loss from radiation is usually permanent.
Other causes of thinning hair are generally self-limiting. Causes that are self-limiting include childbirth, high fever, a severe infection, or major surgery. However, alopecia that accompanies chronic illness may persist indefinitely.
Certain styling techniques can also cause hair damage, hair loss, and hair-follicle damage. These styling techniques include the excessive pulling (traction alopecia) on hair, such as from straightening curly hair. These damaging techniques also include waxes and hot combs, which harm both hair and hair follicles. Damaged hair follicles may shrink, atrophy, or may die completely. Damaged hair follicles may not be able to regrow hair even after the styling techniques are no longer used.
Permanent and temporary hair loss are the two primary categories of baldness; the former due to the destruction of hair follicles, and the latter from transitory damage to the follicles. Out of these two major categories, there can be sub-classified into many types of baldness, each with a different cause. The category of permanent hair loss is dominated by male-pattern baldness, which occurs to some degree in as much as 40 percent of some male populations. A temporary loss of hair occurs fairly commonly after conditions accompanied by high fever but may also be produced by X rays, ingestion of metals (such as thallium, tin, and arsenic) or drugs, malnutrition, some inflammatory skin diseases, chronic wasting diseases, and endocrine disorders. Alopecia areata, a fairly common disorder of unknown cause characterized by sharply outlined patches of sudden complete baldness, is also usually temporary.
Here are some of the more common types of baldness:
The most common type of hair loss is the male-pattern baldness, scientifically known as androgenic alopecia, which accounts for 95% of all hair loss. It occurs more frequently in men than in women. It is a permanent type of hair loss that usually progresses gradually. In men, the hair loss often begins with a characteristic recession of the hairline at the front or thinning of the crown hair until a bald spot appears at the top of the scalp. In some cases, hair loss continues until only a thin rim of hair remains at the sides and back of the head. In women, this condition appears as diffuse hair loss over the entire scalp. By the age of 60, two thirds of men will suffer hair loss; and about one third of women will experience some degree of hair loss.
Male-pattern baldness has a hereditary basis, and may begin at any age after puberty. The baldness varies in degree and seems to be caused by imbalances in the level of male hormones (testosterone and androgens) circulating in the blood and a shortened growth phase in the hair's life cycle. Scalp and other tissues contain an enzyme called 5-alpha reductase. This enzyme converts testosterone to a potent male hormone dihydrotestosterone, or DHT, to be formed in the hair follicle. However, in androgenic alopecia, genetically primed follicles overproduce the hormone. This shortens the active growth phase of the hair life cycle. Eventually, the shortened life cycle leads to degradation of the follicle. The follicle may die or simply shrink to a size that produces only a fine, nonpigmented hair. At a certain point, the hair is too thin and fragile to survive, and baldness occurs.
Male-pattern baldness is usually seen in persons with comparatively heavy body and facial hair and is common among people with origins in the European, white American and Australian geographic races. It is less common among Asians, American Indians, and Africans.
Other Permanent Baldness
Other types of permanent baldness may be the result of scar-producing skin diseases and injuries, inborn lack of hair development, severe injury to hair follicles by chemical or physical agents.
Patchy Hair Loss
Another type of hair loss is the alopecia areata, which leads to patchy hair loss on the scalp. There could be single or several bald spots, with the size of a coin or a bit larger. The bald scalp is often shiny, with a clear border. Alopecia areata is a kind of limited baldness disease which attacks abruptly. It is characterized by the sudden fall of the hair, accompanied with no inflammatory damages and subjective symptoms. It can appear in several parts simultaneously or one after the other. Usually the hair will regrow after several months; but as one patch regrows, sometimes another may appear.
The exact cause of alopecia areata is not known, but it is thought to be the result of the body's immune system attacking the hair follicles. People who are under stress may also suffer from alopecia areata. It can occur at any age and may recur after recovery.
A few patients may lose their whole hair, and the condition is called alopecia capitis totalis. In certain special cases, the patients may lose all the hairs all over the body, including hairs of the eyebrow, armpit, and so on. It is called alopecia universalis.
Traction Alopecia and Trichotillomania
Also known as traumatic alopecia, this kind of hair loss is caused by long-term pulling or twisting on the hair. It could be localized or diffuse hair loss. Certain hairstyles such as tight braids could cause it, though the hair loss is usually reversible once the cause of the pulling is eliminated. It also occurs after excessive application of hair "softeners" such as permanent wave solutions or hot combs.
A temporary hair loss at the hair line, called alopecia marginalis or alopecia liminaris frontalis, caused by chronic traction and commonly seen in blacks, is also a form of traction alopecia, although long, continued traction may cause permanent alopecia.
Trichotillomania refers to a compulsion to pull out one's hair, which causes hair loss.
This is diffuse hair loss caused by administration of various types of drugs.
Associated with psychomotor epilepsy, a condition of not having any hair at birth. The scientific name for this is alopecia congenitalis.
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