Hair Loss - Why? Though humans no longer make use of hair for protection, heat retention, or camouflage, it still remains a very important means by which individuals display and are recognized. Appropriate appearance and grooming are still very important in social organization and the human relationships. The human body contains approximately five million hair follicles while the scalp (prior to any kind of hair loss) contains 100,000-150,000 hair follicles. Blondes have the greatest number of scalp follicles, followed by brunettes. Humans with red hair have the fewest number of scalp follicles. The normal growth rate of scalp hair is one-fourth to one-half inch per month. THE NORMAL HAIR GROWTH CYCLE It is important to understand the normal hair growth cycle to understand why hair loss occurs. The hair follicle is an anatomical structure which evolved to produce and extrude (push out) a hair shaft. Hair is made up of proteins called keratins. Human hair grows in a continuous cyclic pattern of growth and rest known as the "hair growth cycle." Three phases of the cycle exist: Anagen= growth phase; Catagen= degradation phase; Telogen= resting phase. (see diagram "Hair Cycle") Periods of growth (anagen) between two and eight years are followed by a brief period, two to four weeks, in which the follicle is almost totally degraded (catagen). The resting phase (telogen) then begins and lasts two to four months. Shedding of the hair occurs only after the next growth cycle (anagen) begins and a new hair shaft begins to emerge. On average 50-100 telogen hairs are shed every day. This is normal hair loss and accounts for the hair loss seen every day in the shower and with hair combing. These hairs will regrow. Not more than 10 percent of the follicles are in the resting phase (telogen) at any time. A variety of factors can affect the hair growth cycle and cause temporary or permanent hair loss (alopecia) including medication, radiation, chemotherapy, exposure to chemicals, hormonal and nutritional factors, thyroid disease, generalized or local skin disease, and stress. Androgens (testosterone, dihydrotestosterone) are the most important control factors of human hair growth. Androgens must be present for the growth of beard, axillary (underarm), and pubic hair. Growth of scalp hair is NOT androgen-dependent but androgens are necessary for the development of male and female pattern hair loss. MALE PATTERN HAIR LOSS (Androgenetic Alopecia) It is estimated that 35 million men in the United States are affected by androgenetic alopecia. "Andro" refers to the androgens (testosterone, dihydrotestosterone) necessary to produce male-pattern hair loss (MPHL). "Genetic" refers to the inherited gene necessary for MPHL to occur. In men who develop MPHL the hair loss may begin any time after puberty when blood levels of androgens rise. The first change is usually recession in the temporal areas, which is seen in 96 percent of mature Caucasian males, including those men not destined to progress to further hair loss. Hamilton and later Norwood have classified the patterns of MPHL (see illustration of "Norwood-Hamilton Scale"). Although the density of hair in a given pattern of loss tends to diminish with age, there is no way to predict what pattern of hair loss a young man with early MPHL will eventually assume. In general, those who begin losing hair in the second decade are those in whom the hair loss will be the most severe. In some men, initial male-pattern hair loss may be delayed until the late third to fourth decade. It is generally recognized that men in their 20’s have a 20 percent incidence of MPHL, in their 30’s a 30 percent incidence of MPHL, in their 40’s a 40 percent incidence of MPLH, etc. Using these numbers one can see that a male in his 90’s has a 90 percent chance of having some degree of MPHL. Hamilton first noted that androgens (testosterone, dihydrotestosterone) are necessary for the development of MPHL. The amount of androgens present does not need to be greater than normal for MPHL to occur. If androgens are present in normal amounts and the gene for hair loss is present, male pattern hair loss will occur. Axillary (under arm) and pubic hair are dependent on testosterone for growth. Beard growth and male pattern hair loss are dependent on dihydrotestosterone (DHT). Testosterone is converted to DHT by the enzyme, 5¤ -reductase. Finasteride (Propecia®) acts by blocking this enzyme and decreasing the amount of DHT. Receptors exist on cells that bind androgens. These receptors have the greatest affinity for DHT followed by testosterone, estrogen, and progesterone. After binding to the receptor, DHT goes into the cell and interacts with the nucleus of the cell altering the production of protein by the DNA in the nucleus of the cell. Ultimately growth of the hair follicle ceases. The hair growth cycle (see paragraph on "The Normal Hair Growth Cycle") is affected in that the percentage of hairs in the growth phase (anagen) and the duration of the growth phase diminish resulting in shorter hairs. More hairs are in the resting state (telogen) and these hairs are much more subject to loss with the daily trauma of combing and washing. The hair shafts in MPHL become progressively miniaturized, (see illustration of "Miniaturization") smaller in diameter and length, with time. In men with MPHL all the hairs in an affected area may eventually (but not necessarily) become involved in the process and may with time cover the region with fine (vellus) hair. Pigment (color) production is also terminated with miniaturization so the fine hair becomes lighter in color. The lighter color, miniaturized hairs cause the area to first appear thin. Involved areas in men can completely lose all follicles over time. MPHL is an inherited condition and the gene can be inherited from either the mother or father’s side. There is a common myth that inheritance is only from the mother’s side. This is not true. In summary, male pattern hair loss (Androgenetic Alopecia) is an inherited condition manifested when androgens are present in normal amounts. The gene can be inherited from the mother or father’s side. The onset, rate, and severity of hair loss are unpredictable. The severity increases with age and if the condition is present it will be progressive and relentless. Patterns of Female Hair Loss Female hair loss occurs in more than one pattern. If you are a woman with loss of scalp hair, you should seek professional advice from a physician hair restoration specialist. In most cases, female hair loss can be effectively treated. If you are a woman who has started to lose scalp hair, you are not alone if: You are unpleasantly surprised by the hair loss, and You don’t understand why you are losing hair. The patterns of hair loss in women are not as easily recognizable as those in men. Hair loss in men is likely to occur primarily between late teen-age years and age 40-50, in a generally recognizable "male-pattern" baldness known as androgenetic alopecia. Men with male-pattern hair loss may have an expectation of hair loss if they have male relatives who lost hair in a recognizably male pattern (Click here to learn more about male-pattern hair loss). Unlike hair loss in men, female scalp hair loss may commonly begin at any age through 50 or later, may not have any obvious hereditary association, and may not occur in a recognizable "female-pattern alopecia" of diffuse thinning over the top of the scalp. A woman who notices the beginning of hair loss may not be sure if the loss is going to be temporary or permanent—for example, if there has been a recent event such as pregnancy or illness that may be associated with temporary hair thinning. If you are a woman who is worried about loss of scalp hair, you should consult a physician hair restoration specialist for an evaluation and diagnosis. Self-diagnosis is often ineffective. Women tend to have less obvious patterns of hair loss than men, and non-pattern types of hair loss are more frequent in women than in men. Diagnosis of hair loss in a woman should be made by a trained and experienced physician. In women as in men, the most likely cause of scalp hair loss is androgenetic alopecia—an inherited sensitivity to the effects of androgens (male hormones) on scalp hair follicles. However, women with hair loss due to this cause usually do not develop true baldness in the patterns that occur in men—for example, women rarely develop the "cue-ball" appearance often seen in male-pattern androgenetic alopecia. Patterns of female androgenetic alopecia can vary considerably in appearance. Patterns that may occur include: Diffuse thinning of hair over the entire scalp, often with more noticeable thinning toward the back of the scalp. Diffuse thinning over the entire scalp, with more noticeable thinning toward the front of the scalp but not involving the frontal hairline. Diffuse thinning over the entire scalp, with more noticeable thinning toward the front of the scalp, involving and sometimes breaching the frontal hairline. Unlike the case for men, thinning scalp hair in women due to androgenetic alopecia does not uniformly grow smaller in diameter (miniaturize). Women with hair loss due to androgenetic alopecia tend to have miniaturizing hairs of variable diameter over all affected areas of the scalp. While miniaturizing hairs are a feature of androgenetic alopecia, miniaturization may also be associated with other causes and is not in itself a diagnostic feature of androgenetic alopecia. In post-menopausal women, for example, hair may begin to miniaturize and become difficult to style. The precise diagnosis should be made by a physician hair restoration specialist. It is important to note that female pattern hair loss can begin as early as the late teens to early 20s in women who have experienced early puberty. If left untreated, this hair loss associated with early puberty can progress to more advanced hair loss if it is left untreated. Non-Pattern Causes of Hair loss in Women In women more often than in men, hair loss may be due to conditions other than androgenetic alopecia. Some of the most common of these causes are: Trichotillomania—compulsive hair pulling. Hair loss due to trichotillomania is typically patchy, as compulsive hair pullers tend to concentrate the pulling in selected areas. Hair loss due to this cause cannot be treated effectively until the psychological or emotional reasons for trichotillomania are effectively addressed. Alopecia areata—a possibly autoimmune disorder that causes patchy hair loss that can range from diffuse thinning to extensive areas of baldness with "islands" of retained hair. Medical examination is necessary to establish a diagnosis. Triangular alopecia—loss of hair in the temporal areas that sometimes begins in childhood. Hair loss may be complete, or a few fine, thin-diameter hairs may remain. The cause of triangular alopecia is not known, but the condition can be treated medically or surgically. Scarring alopecia—hair loss due to scarring of the scalp area. Scarring alopecia typically involves the top of the scalp and occurs predominantly in women. The condition frequently occurs in African-American women and is believed to be associated with persistent tight braiding or "corn-rowing" of scalp hair. A form of scarring alopecia also may occur in post-menopausal women, associated with inflammation of hair follicles and subsequent scarring. Telogen effluvium—a common type of hair loss caused when a large percentage of scalp hairs are shifted into "shedding" phase. The causes of telogen effluvium may be hormonal, nutritional, drug-associated, or stress-associated. Loose-anagen syndrome—a condition occurring primarily in fair-haired persons in which scalp hair sits loosely in hair follicles and is easily extracted by combing or pulling. The condition may appear in childhood, and may improve as the person ages. Diagnosis and Treatment If you are a woman with thinning or lost scalp hair, your first necessary step is to have the condition correctly diagnosed by a physician hair restoration specialist. After a diagnosis is made, the physician will recommend an approach to effective medical or surgical treatment (Click on Surgical Treatment and Non-Surgical Treatment). References Olsen EA (ed). Female Pattern Hair loss: Clinical Features and Potential Hormonal Factors. J Amer Acad Dermatol 2001; 45:S-70-S80. Olsen EA. Hair disorders. In: Freedberg IM et al (eds.) Fitzpatrick’s Dermatology in General Medicine, 5th ed. New York: McGraw-Hill, 1999:729-751. OTHER CAUSES OF HAIR LOSS ALOPECIA AREATA Alopecia areata (AA) is a recurrent disease, which can cause hairloss in any hair-bearing area. The most common type of AA presents as round or oval patches of hair loss most noticeably on the scalp or in the eyebrows. The hair usually grows back within 6 months to one year. Most patients will suffer episodes of hair loss in the same area in the future. Those who develop round or oval areas of hair loss can progress to loss of all scalp hair (alopecia totalis). The cause of AA is unknown but commonly thought to be an autoimmune disorder (the body does not recognize the hair follicles and attacks them). Stress and anxiety are frequently blamed by patients as the cause of their hair loss. The most common treatment is with steroids (cortisone is one form) either topically or by injection. The outcome of treatment is good when the AA process is present less than one year and poor, especially in adults, if the disease has been present for longer periods of time. Minoxidil (Rogaine®) can help to regrow hair. Surgical treatment of this disorder is not recommended. If you have questions concerning Alopecia areata, please contact an ISHRS physician. TRACTION ALOPECIA Traction alopecia is caused by chronic traction (pulling) on the hair follicle and is seen most commonly in African-American females associated with tight braiding or cornrow hair styles. It is generally present along the hairline. Men who attach hairpieces to their existing hair can experience this type of permanent hairloss if the hairpiece is attached in the same location over a long period of time. Trichotillomania is a traction alopecia related to a compulsive disorder caused when patients pull on and pluck hairs, often creating bizarre patterns of hairloss. In long term case of trichotillomania, permanent hairloss can occur. Could I be the cause of my own bald spot? Click here. SCARRING ALOPECIAS The diseases which cause permanent hairloss do so when scar tissue replaces destroyed normal tissue. They include: Lupus Erythematosus- occurs more frequently in females than in males and is more common in adults than in children. Scleroderma- hair loss tends to be slowly progressive Infectious Agents- Bacterial folliculitis, fungal infections, herpes zoster Hair Loss—Diagnostic Techniques Before recommending or performing a hair restoration procedure, a ISHRS physician will conduct a scalp examination to determine the cause of hair loss. If the examination indicates that hair loss may be due to a condition other than male or female pattern baldness, the physician will seek the cause with other diagnostic measures. In some cases an underlying condition may have to be treated before hair restoration is undertaken. Hair Pull A hair pull is a diagnostic procedure used in virtually every patient with a complaint of unexplained hair loss, to assess the presence or absence of any abnormalities in the hair growth cycle. About 25 to 50 hairs are removed from the scalp by a series of gentle hair pulls. Normally only a few hairs are dislodged with each pull. When more are removed the possibility of an abnormality of hair growth cycling is indicated; the ends of the pulled-out hairs may be examined under a microscope to evaluate the condition of the hair shaft and the bulb (the end of the hair shaft extracted from the hair follicle). Variations of the hair pull are the phototrichogram and hair window: Phototrichogram—hairs are clipped or shaved in an area of the scalp and consecutive photographs taken over a period of 3 to 5 days to determine the pattern of hair growth. Hair window—hairs are clipped or shaved in an area of the scalp and hair growth is evaluated over the next 3 to 30 days. Abnormalities of hair growth cycling is a relatively uncommon cause of hair loss but may occur at any age. Underlying causes of these abnormalities include thyroid hormone imbalance, nutritional deficiencies, side effects of certain drugs, anemia and other systemic illness, and psychological stress. Biopsy A biopsy of the scalp is usually performed only if additional information is needed to evaluate the mechanism of hair loss inside the hair follicle. Biopsy is not necessary in the great majority of patients evaluated for hair loss and hair restoration. Hair Shaft Evaluation If a hair shaft abnormality or infection is suspected, the hair shafts removed from the scalp by hair pull are examined under a microscope. Hair shaft abnormalities and fungal, bacterial or viral infection can be responsible for hair loss associated with hair breakage, hair shedding and hair that is unruly. Hair Analysis Hair analysis is a laboratory test performed if a hair shaft abnormality needs to be assessed for (1) altered hair-protein profile due to an inherited abnormality, or (2) drug ingestion or heavy metal contamination. Hair analysis is ordered by a hair specialist physician only to determine the cause and mechanism of a hair shaft abnormality. The test has no value for the diagnosis of systemic disease or nutritional status, contrary to claims by non-physician "hair analysis specialists". Fortunately, most persons seeking hair restoration in the U.S. are among the 80 million men and women who have male and female pattern hair loss, a condition simple to diagnose and easy to treat. Extensive diagnostic work-ups for these easily recognized conditions are usually not necessary. There are other causes of hair loss, however, and it is essential that the cause of hair loss be evaluated before hair restoration is undertaken. Contact one of our ISHRS physicians by using the Find a Doctor database.