What Is Hair Loss?
Theis a natural phenomenon in all hair-baring animals that normally occurs during the hair growth cycle. It is estimated that most individuals (assuming they have a full head of hair) lose about 100 scalp hairs over a 24-hour period. Hair loss can become a cosmetic problem when it occurs in the wrong place at the wrong time in the wrong individual. from damage to the hair shaft, which may cause breakage close to the scalp. This sort of damage is often caused by exogenous chemicals used to alter the physical characteristics of the hair shaft (hair dye, etc.) or other forms of self-manipulation.
Physicians divide cosmetically significant hair loss into two categories.
Scarring alopecia: This sort of irreversible hair loss is characterized by damage to the underlying skin which results in scarring that destroys the hair follicle and its potential for regeneration. A simple visual examination is usually sufficient to diagnose this problem, although occasionally a biopsy may be necessary. Certain skin diseases as well as physical trauma produce this sort of damage.
Non-scarring alopecia: This potentially reversible type of hair loss is very common and can be due to many causes, including certain diseases, drugs, aging, diet, as well as a genetic predisposition for hair loss called androgenetic alopecia (common balding).
There are three cycles of hair growth: growing (80% of follicles), resting, and shedding. In human hair, each follicle cycles at its own individual rate as opposed to most animals, where these cycles change with the season, and all hairs are in the same part of the cycle at the same time. This is why animals grow a thicker coat in the fall and shed most in the spring and why human beings do not shed. Unlike most animals, in humans, each hair has its own pattern of growing, resting, and shedding.
Each person sheds hair and regrows hair every day.
When this balance is disturbed and more hairs are shed than are regrown, alopecia or hair loss results.
What Causes Hair Loss?
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Common causes of hair loss
a non-scarring alopecia (androgenetic alopecia), is genetically determined. In afflicted postpubertal individuals, hair follicles in the center of the scalp and over the temple begin to miniaturize, producing small, fine hairs which are difficult to see. This process is due to the metabolism of testosterone by an enzyme in the hair follicle. Generally, hair follicles over the ears and around the posterior of the scalp do not possess this enzyme so a fringe of normal hair is maintained.
Female-pattern baldness is very similar to its male counterpart, it occurs after menopause, and often spares the frontal hairline. It usually involves an overall thinning of hair.
Telogen effluvium is a phenomenon that occurs mostly in females, especially post pregnancy when there is an entirely, spontaneously reversible shedding of scalp hair.
Alopecia areata, a non-scarring alopecia, is thought to be an autoimmune disease and is characterized by distinct, localized, sharply marginated areas of hair loss. This characteristically spontaneously remits but occasionally can result in the loss of 100% of all body hair.
Medications such as allopurinol (Zyloprim), oral vitamin A analogs, chemotherapeutic drugs, and warfarin (Coumadin)
Poor nutrition and strict dieting and certain types of bariatric surgery
Uncommon causes of alopecia
Infections such as syphilis and fungal infections
Skin diseases such as lupus and lichen planus
Masculinizing hormonal problems such as polycystic ovary syndrome
Women’s Hair Loss
, PCOS, alopecia areata, and ringworm, among others. See pictures of other causes of women’s hair loss, and learn about treatments for thinning hair.