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Usual hair loss (baldness)

 
, medical expert
Last reviewed: 25.06.2018
 
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Normal alopecia (syn: androgenetic alopecia, androgenic alopecia, androgenic alopecia)

The change of hair, which begins before birth, occurs throughout the life of a person. Man is not the only primacy, whose baldness is a natural phenomenon associated with puberty. Minor baldness develops in adults of orangutans, chimpanzees, tailless macaques, and in the latter this process has the greatest similarity with that of humans.

Ordinary baldness can be noticeable in healthy men by age 17 and in healthy women by 25-30 years. During hair loss, terminal hair becomes thinner, short and less pigmented. Reduction of the size of the follicles is accompanied by a shortening of the anagen phase and an increase in the amount of hair in the telogen phase.

"Androgenic" this type of baldness called N. Orentreich in 1960, emphasizing the leading role of androgen's influence on androgen-dependent hair follicles.

Androgenic alopecia is often incorrectly called male pattern baldness, which leads to an unjustifiably rare diagnosis of it in women, especially when assessing the early manifestations of alopecia, since the pattern of hair loss in women is different than that of men.

The nature of hair loss in normal baldness

The first, and still significant, classification of types of normal baldness belongs to the American doctor J. Gamilton (1951). Having examined more than 500 people of both sexes from the age of 20 to 79 years, the author singled out 8 types of baldness.

Baldness in the parietal region is not present Type I

Hair preserved;

Type IA The front line of hair growth recedes, the forehead becomes higher
Type II bald patches on the temples on both sides;
Type III border crossing point;
Type IV deep frontal-temporal bald patches. Usually there is also a bald head along the middle line of the forehead. In the elderly, this degree of hair loss in the frontotemporal area can be combined with hair thinning on the crown
Alopecia in the parietal region is Type V enlarged frontal-temporal bald patches and pronounced outcrop of the crown;
Type VI and VIA increased hair loss in both areas, which gradually merge;
Type VII an increase in the frontotemporal and parietal zones of baldness, separated only by a line of rare hair;
Type VIII complete fusion of these areas of alopecia.

J. Hamilton described the progression from a normal pre-pubertal hair growth pattern (type I) to type II, which develops after reaching puberty in 96% of men and 79% of women. Alopecia of V-VIII types is typical for 58% of men over 50 years old with progression to 70 years. Later it was observed that men who have a bald spot in the parietal region formed before the age of 55 are more likely to suffer from coronary artery disease.

In women, hair loss of V-VIII types does not occur. At 25% of women by the age of 50 develops type IV alopecia. In some women with hair loss type II hair growth is restored to normal (type I) during menopause. Although these types of baldness are sometimes found in women, nevertheless androgenic alopecia in women is more often diffuse. In this connection, for the evaluation of normal baldness in women it is more convenient to use the classification of E. Ludwig (1977), who distinguished three types of alopecia.

  • Type (stage) I: Noticeable, oval, diffuse hair thinning in the fronto-parietal area, along the front line of growth, the thickness of the hair is not changed.
  • Type (stage) II: More noticeable diffuse hair thinning in the indicated area.
  • Type (stage) III: Almost complete or complete alopecia of the indicated area. The hair surrounding the patch of alopecia is preserved, but their diameter is reduced.

The types (stages) of alopecia identified by J. Gamilton and E. Ludwig are certainly not a method of measuring the degree of hair loss, but are convenient for practical work, in particular, in evaluating the results of clinical trials. In surgical correction of alopecia, the Norwood classification (1975), which is a modified classification of Hamilton, is a universally accepted standard.

It is essential to change the pre-pubertal hair growth in adult hair. The vastness and speed of these changes is determined by the genetic predisposition and the level of sex hormones in both sexes. You can not also exclude the role of living conditions, the nature of nutrition, the state of the nervous system and other factors that affect the process of aging and hair loss.

The discovery of the role of androgens in the pathogenesis of normal alopecia served as an excuse for judging the increased sexuality of balding males. However, this statement is devoid of scientific justification. There is also no relationship between hair loss on the head and their thick growth on the trunk and extremities.

Heredity and alopecia

The enormous frequency of normal alopecia makes it difficult to determine the type of inheritance. The present level of knowledge indicates the absence of genetic homogeneity.

Some authors allocate in men the usual baldness with early (up to 30 years) and late (over 50 years) beginning. It is established that in both cases, baldness is inherited and depends on androgenic stimulation of the hair follicles.

It was suggested that baldness is determined by one pair of sex-dependent factors. According to this hypothesis, common baldness develops in both sexes with genotype BB and in men with genotype Bv. Women with BV genotype, as well as men and women with a genotype, are not predisposed to baldness.

When studying the immediate relatives of women with normal hair loss it was found that a similar process took place in 54% of men and

25% of women are over 30 years old. It has been suggested that common baldness develops in heterozygous women. In men, this process is due either to the dominant type of inheritance with increased penetrance, or there is a multifactorial nature of inheritance.

Clarification of the type of inheritance can be facilitated by the detection of a biochemical marker of baldness. So, two groups of young men with different activity of the 17b-hydroxysteroid enzyme in the skin of the scalp have already been established. In families of patients with high activity of this enzyme, many relatives suffered marked alopecia. On the contrary, low activity of the enzyme is associated with hair preservation. Studies in this promising direction are continuing.

Communication of seborrhea and normal alopecia

The relationship between increased salinity and normal alopecia is seen long ago and has been reflected in the frequent use of the term "seborrheic alopecia" as a synonym for normal alopecia. The function of the sebaceous glands, as well as androgen-dependent hair follicles, is under the control of androgens. Androgens cause an increase in the size of the sebaceous glands and the amount of excreted fat, which was proven when testosterone was administered to boys in the pre-pubertal period. The appointment of testosterone to adult men did not have such an effect, since, probably, during puberty, sebaceous glands are maximally stimulated by endogenous androgens at their normal level. In addition to testosterone, the production of sebum in men is stimulated by other androgens: dehydroepiandrosterone and androstenedione. Anlrosterone does not have such an effect. However, in the gravimetric study of the production of sebum on the bald pate, compared to other areas of the scalp, and also in comparison with these indices in non-balding subjects, no significant differences were found.

In women, the production of sebum increases even with a slight increase in the level of circulating androgens. It is generally believed that the usual, or androgenic, baldness in women is an integral part of the hyperandrogenia syndrome, which, in addition to seborrhea and alopecia, also includes acne and hirsutism. However, the degree of expression of each of these manifestations can vary widely.

The frequent washing of the head, recommended by many cosmetologists, does indeed reduce hair loss during the following days, but this is explained by the removal of the hair that is at the end of the telogen phase.

trusted-source[1], [2], [3], [4], [5], [6], [7], [8]

How does baldness develop?

Changes begin with focal perivascular basophilic degeneration of the lower third of the connective tissue vagina of the hair follicle located in the anagen phase. Later, at the level of the excretory duct of the sebaceous gland, the perifollicular lymphohistiocytic infiltrate is formed. The destruction of the connective tissue vagina determines the irreversibility of hair loss. Approximately 1/3 of the biopsy specimens are detected by multinucleated giant cells surrounding the fragments of the hair. In the place of the formed bald head, most follicles are short, reduced in size. It should be mentioned that horizontal sections of the biopsy are more convenient for morphometric analysis.

Under the influence of ultraviolet rays in areas devoid of hair protection, degenerative changes in the skin develop.

With the help of modern research methods it is shown that the appearance of baldness is accompanied by a decrease in blood flow. Unlike the richly vascularized normal follicle, the vessels surrounding the root of the hair follicle are small and tortuous, with difficulty. It remains unclear whether the reduction in blood flow is primary or secondary to alopecia. It was suggested that the same factors are responsible for the changes in both vessels and follicles.

In normal hair loss, the anagen phase of the hair cycle is shortened and, accordingly, the amount of hair in the telogen phase is increased, which can be determined from the trichogram in the frontopariet area long before hair loss becomes obvious.

Miniaturization of hair follicles leads to a decrease in the diameter of the hair produced by them, sometimes 10-fold (up to 0.01 mm instead of 0.1 mm), which is more pronounced in women than in men. Some follicles are delayed with entry into the anagen phase after hair loss, the mouth of such follicles look empty.

The pathogenesis of normal alopecia (hair loss)

Currently, the role of androgens in the development of normal alopecia is universally recognized.

The hypothesis of androgenic nature of baldness is quite justified, as it allows to explain a number of clinical observations: the presence of baldness in humans and other primates; the presence of the disease in men and women; combination of baldness in persons of both sexes with seborrhea and acne, and in some women with hirsutism; arrangement of hair loss zones on the scalp.

J. Hamilton showed the absence of baldness in eunuchs and in castrated adult men. The appointment of testosterone caused baldness only in genetically predisposed subjects. After testosterone withdrawal, the progression of alopecia stopped, but hair growth did not resume.

The assumption of hypersecretion of testicular or adrenal androgens in balding men has not been confirmed. Thanks to modern methods of determining free and bound androgens, it has been shown that the normal level of androgens is sufficient for the appearance of baldness in genetically predisposed men.

Women have a different situation; the degree of alopecia depends in part on the level of circulating androgens. Up to 48% of women with diffuse baldness suffer from polycystic ovaries; hair loss on the head in such patients is often combined with seborrhea, acne and hirsutism. The maximum changes in hair growth occur after menopause, when the level of estrogen falls, and "androgen supply" remains. During the menopause, androgens cause hair loss only in genetically predisposed women. With a less pronounced genetic predisposition, baldness develops only with increased production of androgens or medication with androgen-like action (for example, progestrogens as oral contraceptives, anabolic steroids that athletes often take). At the same time, in some women, even a sharp increase in the level of androgens does not cause any significant alopecia, although the manifestation of hirsutism in such cases always occurs.

Since the establishment of the leading role of androgens in the development of normal balding, the efforts of many scientists have been focused on revealing the mechanism of their action. Brilliant results of transplantation of autografts containing hair follicles from the occipital region to the balding zone convincingly showed that each hair follicle possesses a genetic program that determines its response to androgens (androgen-sensitive and androgen-resistant follicles).

The effect of androgens on hair follicles varies in different parts of the body. So, androgens stimulate the growth of the beard, the growth of pubic hair, in the armpits, on the chest and, on the contrary, slow the growth of hair on the head in the area of the androgen-sensitive follicles in genetically predisposed subjects. Hair growth is controlled by different hormones: testosterone (T) stimulates the growth of pubic and axillary hair; dihydrotestosterone (DTS) causes the growth of the beard and the usual hair loss on the scalp.

The emergence of normal baldness is determined by two key factors: the presence of androgen receptors and the activity of androgen-converting enzymes (5-alpha-reductase I and II types, aromatase and 17-hydroxy-steroid dehydrogenase) in various parts of the scalp.

It was found that in the fronto-parietal region in men the level of androgen receptors is 1.5 times higher than in the occipital region. The presence of androgen receptors is demonstrated in the culture of dermal papilla cells taken from the scalp of both balding and non-algal subjects, and is indirectly confirmed by the good effect of antiandrogens in diffuse alopecia in women. In the cells of the matrix and the outer root vagina of the hair follicle, these receptors are not detected.

The second key factor in the pathogenesis of normal alopecia is the change in the balance of enzymes involved in the metabolism of androgens. 5a-reductase catalyzes the process of conversion of T into its more active metabolite - DTS. Although I type 5a-reductase predominates in the extracts of the scalp tissue, type II of this enzyme is also found in the hairy vagina and dermal papilla. Moreover, it is known that individuals with congenital deficiency of type II 5-reductase do not suffer from ordinary baldness. The DTS receptor complex has a high affinity for nuclear chromatin receptors, as a result of their contact, the process of inhibition of hair follicle growth and its gradual miniaturization is included.

While 5a-reductase promotes the conversion of T into DTS, the aromatase enzyme converts androstenedione to estrone and T to estradiol. Thus, both enzymes play a role in the occurrence of normal alopecia.

When studying the metabolism of androgens in the scalp of the scalp, increased activity of 5-reductase in the centers of alopecia was revealed. In men, the activity of 5a-reductase in the skin of the frontal region is 2 times higher than in the occiput; the activity of aromatase in both areas is minimal. In women, the activity of 5a-reductase in the fronto-parietal region is also 2 times higher, but the total amount of this enzyme in women is half that of men. The activity of aromatase in the scalp of the scalp is higher in women than in men. Preservation of the anterior hair line in most women with normal hair loss is probably due to the high activity of aromatase, which converts androgens to estrogens. The latter, as is known, have an antiandrogenic effect due to their ability to increase the level of proteins that bind sex hormones. Intensive hair loss in men is associated with low aromatase activity and. Respectively, with increased TTP production.

Some steroidal enzymes (3alpha, 3beta, 17beta-hydroxydrosteroids) have the ability to convert weak androgens, such as dehydroepiandrosterone. In more powerful androgens, having swap tissue targets. The concentration of these enzymes in the balding and non-sliced areas of the head is the same, but their specific activity in the frontal region is much higher than in the occipital region, and in men compared with women this figure is much larger.

It is also known that the appointment of growth hormone to men with a deficiency of this hormone increases the risk of androgenic alopecia. This effect is explained either by direct stimulation of androgen receptors by an insulin-like growth factor-1, or this factor acts indirectly, activating 5a-reductase and, accordingly, accelerating the conversion of T to TPA. The function of sex hormone binding proteins has been little studied. It has been suggested that a high level of these proteins makes T less accessible to metabolic processes, reducing the risk of baldness.

It is necessary to take into account the influence on the process of alopecia cytokines and growth factors. Accumulating data testify to the important role of regulation of expression of cytokine genes, growth factors and antioxidants during the initialization of the hair cycle. Attempts are being made to identify key molecules of cyclic hair growth activity. It is planned at the subcellular and nuclear level to investigate the changes caused by these substances in their interaction with the cells of the hair follicle.

Symptoms of Alopecia

The main common for men and women, a clinical sign is the change of terminal hair more thin, short and less pigmented. Reduction of the size of the hair follicles is accompanied by a shortening of the anagen phase and, correspondingly, an increase in the amount of hair in the telogen phase. With each hair cycle, the size of the follicle decreases and the cycle time shortens. Clinically, this is manifested in an increase in hair loss in the telogen phase, which causes the patient to consult a doctor.

In men, the process of alopecia begins with a change in the front-temporal line of hair growth; it recedes from the sides, forming the so-called "professorial angles", the forehead becomes higher. It is noted that changes in the frontal line of hair growth do not occur in men with family pseudogermacrodism. Associated with a deficiency of 5a-reductase. As the progress of alopecia progresses, the hair in the pre- and postauric areas changes the texture - they look like a beard (mustache). Gradually deepened bitemporal crescents, there is a thinning of hair, and then a bald patch in the parietal region. Some men in the parietal region retain their long hair. The rate of progression and the pattern of normal baldness are determined by genetic factors, but the influence of unfavorable environmental factors can not be ruled out. Characteristically, with normal baldness, hair in the lateral and posterior parts of the scalp (in the form of a horseshoe) is completely preserved. The sequence of hair loss in men is described in detail by J. Gamilton.

In women, the frontal line of hair growth usually does not change, there is a diffuse thinning of the hair in the frontal parietal area. More subtle and fleece hair "scattered" among normal hair. Characteristic of the expansion of the central part. This type of baldness is often described as "chronic diffuse alopecia". Sometimes there is partial alopecia parietal region, but diffuse alopecia is much more characteristic. A consistent change in the clinical manifestations of alopecia "according to the female type" was described by E. Ludwig. The change in the pattern of hair growth occurs in all women after puberty. The rate of these changes is very low, but it rises after the onset of menopause. It is known that progesterone-dominant contraceptives increase hair loss. Women with rapid progression of normal baldness, as well as women with a gradual onset of alopecia combined with dysmenorrhea, hirsutism and acne, need a thorough examination to identify the cause of hyperandrogenism.

Focal alopecia

Focal (nest) baldness is characterized by the appearance of single or multiple rounded patches of alopecia of various sizes, which can be placed on the surface of the head, or around the eyebrows, eyelashes, or beard. During the development of the disease, the surface area of such foci becomes larger, they can also connect with each other and take an arbitrary shape. With an absolute loss of hair, baldness is considered total. If the hair disappears from the surface of the body, it is a universal baldness. Focal alopecia progresses quickly enough, but often hair growth itself resumes. However, in approximately thirty percent of cases, the disease can take a cyclic form with a periodic alternation of hair loss and renewal. The main factors provoking the development of focal alopecia include malfunctions in the immune system, hereditary predisposition, the negative impact of stress and environmental factors, traumatic and acute pathologies. Focal alopecia in most cases is treated with corticosteroids, which are part of various creams, tablets and injectable solutions. It is also possible to use drugs that enhance the production of corticosteroids in the body. But it should be noted that such funds can only contribute to the growth of hair in affected areas and are not capable of influencing the causes of the disease and preventing the re-emergence of foci of alopecia.

trusted-source[9], [10], [11]

Hair loss in men

Alopecia in men is often androgenetic. The causes of the development of such a disease are associated with a genetic predisposition. The male hormone testosterone begins to exert a destructive effect on the hair follicles, resulting in hair becoming weaker, becoming thinner, shortening and losing color, and the bald patches appear on the head. Years after the development of androgenetic baldness, follicles completely lose the ability to form hair. Hair loss in men can be associated with prolonged stressful situations, as a result of which there is a narrowing of the vessels of the skin of the head, because of which there is a shortage of food in the roots of hair and they fall out. Some medicines, for example, such as aspirin, diuretics, antidepressants, can give side effects in the form of hair loss. In diseases of the endocrine system, alopecia can be localized in the eyebrow, forehead or occiput. The hair is first dried, tarnished, thin and sparse, and then completely dropped out. It is also believed that the risk of developing baldness can also be caused by nicotine dependence, which increases the production of estrogens in the body and disrupts blood flow in the skin.

Alopecia in women

Alopecia in women can be associated with the following reasons:

  • Damage to the hair follicles due to the constant excessive hair pulling or coarse pulling, for example, with careless combing.
  • Too frequent use of a hair dryer, curling iron, ironing for hair straightening, cosmetic means, which leads to weakening and thinning of hair and their further loss.
  • Failure in the functioning of the ovaries and adrenal glands, hormonal abnormalities in the body.
  • Intoxication, infectious pathology.
  • Cicatricial changes in skin caused by trauma, neoplasm, severe infections.

To diagnose the causes of baldness, a hair trichogram is performed and a blood test is performed. Using the trichogram, the condition of not only the hair itself, but also the hair follicle, bulb, bag, etc., is examined. And determine the ratio of hair growth at different stages. More than men, women are prone to diffuse baldness, which is characterized by an intense process of hair loss. Often after eliminating the cause that causes diffuse hair loss, the hair can recover within three to nine months, since the hair follicles do not die and continue to function.

trusted-source[12], [13], [14], [15], [16], [17], [18], [19]

Alopecia in children

Alopecia in infants can be observed in the forehead and occiput and is often associated with constant friction of the child's head surface against the pillow, since in infancy the baby spends most of the time in the lying position. Hormonal changes that occur in the first year of a baby's life can also cause hair loss. At an older age, the cause of hair loss can be damage to the hair shaft, which can occur with a constant strong pulling of the hair, as well as chemical effects. Such a phenomenon as trichotillomania, when a child intensively and often involuntarily pulls her hair, can also cause them to fall out. This phenomenon can be caused by neurotic conditions, the diagnosis and treatment of which should be carried out by a qualified specialist. Among the causes of baldness in children is often found such a disease as ringworm, resulting from the defeat of the skin of the head, as well as eyelashes and eyebrows fungal infection. Foci of lesion in such cases, as a rule, round or oval, the hair becomes fragile and subsequently falls out. Treatment is usually carried out with antifungal drugs, as an auxiliary tool, shampoo "Nizoral" can be used for two months. Shampoo is used twice a week, and for prevention purposes - once every fourteen days. After applying to the scalp, the shampoo is left on the hair for about five minutes, after which it is washed off with water.

trusted-source[20], [21], [22]

Diagnosis of alopecia

Diagnosis of normal baldness in men is based on the following criteria:

  • the onset of hair loss in the pubertal period
  • the nature of changes in hair growth (symmetrical btemteporalnye bald patches, thinning of hair in the frontotemporal area)
  • miniaturization of hair (decrease in their diameter and length)
  • anamnestic data on the presence of normal alopecia in the patient's relatives

In general, these same criteria are also used to diagnose normal baldness in women. The only exception is the nature of the change in hair growth: the front line of their growth does not change, there is a diffuse hair thinning in the fronto-parietal region, the central part is widened.

When collecting anamnesis, women should pay attention to a recent pregnancy, contraceptive use, endocrine system disorders. In favor of endocrine pathology may indicate:

  • dismenorrhea
  • infertility
  • seborrhea and acne
  • hirsutism
  • obesity

Women who have hair loss associated with any of these symptoms need a thorough examination to determine the cause of hyperandrogenism (polycystic ovary, congenital adrenal hyperplasia with late onset). In some patients, despite the clinically distinct syndrome of hyperandrogenism (seborrhea, acne, hirsutism, diffuse alopecia), endocrine pathology can not be identified. In such cases, probably, there is a peripheral hyperandrogenia in the background of a normal serum level of androgens.

Diagnosing normal hair loss, do not forget about other possible causes of hair loss. Most often, normal baldness can be combined with chronic telogen hair loss, due to the symptoms of normal baldness become more noticeable. In these cases, patients of both sexes need an additional laboratory examination, including a clinical blood test, serum levels of iron, thyroxine and thyroid stimulating hormone, etc.

One of the objective methods for diagnosing normal alopecia is the trichogram - a method of microscopic examination of distant hair, which allows one to get an idea of the ratio of hair in the phase of anagen and telogen. To obtain reliable results of the study, the following conditions must be observed:

  1. Remove at least 50 hairs, since with a small number of hairs, the standard deviation is too large.
  2. Hair should not be washed for a week before the examination to avoid premature hair removal, approaching the end of the telogen phase; otherwise, artificially reduces the percentage of hair in this phase.
  3. Hair must be removed with a sharp movement, as the roots of the hair are damaged less than with slow traction.

The bulbs of the removed hair are stained with 4-dimetyl-aminocinnamaldehyde (DACA), selectively regulating with citrine, which contain) only in the inner root vagina. The hair bulbs in the telogen phase, devoid of the inner shell, do not stain DACA and look small unpigmented and rounded (club). For hair in the anagen phase, elongated pigmented bulbs, surrounded by an internal root vagina, which DACA stains in a bright red color.

In normal hair loss on the trichogram of hair taken in the fronto-parietal region, an increased amount of hair is detected in the telogen phase and, correspondingly, an anagen / telogen index decrease (in the norm of 9: 1); dystrophic hair is also found. In the temporal and occipital areas, the trichogram is normal.

Histological examination is not used as a diagnostic method.

trusted-source[23], [24], [25], [26], [27], [28], [29], [30]

How to stop baldness?

To accurately answer the question of how to stop baldness, you need to undergo a preliminary examination in order to identify the causes that cause hair loss. In the treatment of androgenetic baldness, such drugs as minoxidil and finasteride (recommended for use by males) are considered effective. Minoxidil can influence the structure and activity of hair follicle cells, slowing hair loss and stimulating their growth. The drug is applied to dry scalp with a special applicator, avoiding contact with other areas of the skin, use such a device no more than twice a day for one milliliter. Within four hours after applying the drug, the head can not be wetted. Minoxidil is contraindicated in children, as well as individuals who have individual intolerance to the components that make up the drug. It is forbidden to apply such a remedy to the damaged skin, for example, with sunburn. Minoxidil has no effect if baldness was caused by taking any medications, improper nutrition, or excessive constriction of hair into the bundle. In order to stop hair loss, a method such as hair transplantation can be used. Hair follicles from the occipital and lateral segments of the head are transferred to the centers of alopecia. After such transplantation, the follicles continue to function normally and produce healthy hair.

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