Why Do We Lose Hair
Hair loss, known as Alopecia, is a common condition. It does not hurt, it is not life-threatening, but it is a source of emotional distress and can have profound effects on the quality of life of those who suffer this condition. Millions of men and women in the US are affected by hair loss and/or hair thinning to some degree and statistics show those numbers are increasing. In our society, hair is intimately related to beauty and youth, but hair also plays an important role in the protection of the scalp from UV rays, as well as extreme cold or hot temperatures. Furthermore, scientists are studying the role of hair as a sense organ and how the brain gathers information from our hair.
Hair loss is caused by a wide range of factors which are still not fully understood. One of the major aspects that have been linked to hair loss is heredity, the genes passed from our parents. Stress, our lifestyle habits - including diet and exercise -, environmental factors, our immune system, hormonal imbalances, and disease are other elements that have a major influence on the loss of hair. Science and research in this field show that there are many complex factors combined in the development of hair thinning and hair loss. This important concept must be taken in consideration when we approach a treatment that should address each one of these aspects.
Structure of the Hair
Hair Growth Cycle
There are 3 phases:
- Anagen: or growing phase. It lasts years.
- Catagen: or transition phase. It lasts weeks.
- Telogen: or resting phase. It lasts months
Causes of Hair Loss
The number 1 cause of hair loss is heredity, but in a considerable number of cases, the source is not fully understood or represents the combination of overlapping issues.
Let’s review the most common ones:
(also known as patterned baldness)
Male Pattern Hair Loss accounts for 95% of the cases of hair loss in men. It may begin in the front, the sides and/or the crown of the head.
Typically, 80% of these men have elevated androgen levels associated with the presence of an androgen receptor in their chromosome 20 that makes their hair follicles be very sensitive to the hormone DHT (de-hydro-testosterone).
Testosterone 5-alpha-reductase type II DHT
DHT binds to the androgen receptors of the hair follicles, and affects hair health by shortening the hair growing phase, and shrinking the hair follicles. This process is called miniaturization, and results in short, thin hair that ends up shedding.
.Female Pattern Hair Loss is characterized by generalized thinning of the hair, but the frontal hairline is maintained.
FPHL is very common and actually, less than 45% of women reach the age of 80 with a full head of hair.
Androgenic alopecia with sensitivity to DHT is the most common type of presentation in post menopausal women. Other causes of FPHL are other hormonal imbalances (thyroid disease, etc), emotional distress, nutritional deficiencies and medications.
Less common causes of Hair Loss
Telogen Effluvium(TE) is a condition in which there is an increased number of dormant hair follicles (resting or telogen phase) resulting in a generalized and prominent hair shedding. It affects adults, develops rapidly, but it is not permanent.
Triggers of this condition are: childbirth, vaccinations, crash diets, physical trauma, surgery, emotional distress.
Anagen Effluvium is frequently seen in patients who are taking cancer medications or in cases of accidental ingestion of toxic products. This condition is temporary.
Alopecia Areata(AA) affects 2% of the population and it is considered an autoimmune disease. It can affect people of all ages. It presents suddenly as a well defined bald patches on the scalp, but some patients present with baldness of the entire scalp (alopecia totalis) and others loose the hair of the entire body (alopecia universalis) The condition is reversible but it is recurrent over time, with periods of hair loss and regrowth.
Traction Alopecia is linked to tightly pulled hairstyles. It most commonly affects the frontal and temporal hairline. Although it is initially a reversible condition, if this excessive traction is not removed, permanent alopecia may develop. Other cosmetic habits that may induce alopecia are thermal treatments (blow dryers, curling irons), chemical straighteners, relaxers.
Trichotillomania: is a debilitating condition characterized by recurrent pulling out of one’s own hair, leading to hair loss. The typical age of onset is at a young age (10-13 years) and there is a familiar component.
Prescription Drugs Associated with Hair Loss: taking any of these medications may cause hair loss. (Link to page prescription drugs associated with hair loss)