Circular alopecia

Circular alopecia (syn.: circular alopecia, focal alopecia, nesting baldness, pelada) is a disease characterized by the appearance of a round or oval bald spot with clear boundaries and outwardly unchanged skin. Limited forms of the disease can progress to complete hair loss on the scalp (total alopecia) and hair loss on the entire body (universal alopecia).

Patients with circular alopecia (CA) account for about 2% of dermatological patients. Both sexes are equally susceptible to this disease, with an increase in incidence between the ages of 20 and 50.

Causes of circular alopecia

The cause of circular alopecia is still unknown. A wide variety of associated diseases and unpredictability of the course allow us to consider circular alopecia a heterogeneous clinical syndrome, in the development of which the following factors play an important role:

1. Emotional stress is considered by most authors to be an important trigger factor in at least some cases of the disease. This opinion is based on clinical observations in which stress preceded the onset of circular alopecia and its relapses, as well as on the effectiveness of hypnotherapy and sleep therapy. An attempt to objectively assess the psychological status of patients showed that 90% of patients had abnormalities, and in 30% of them psychological disorders could be the cause of the disease or have a negative impact on its course. It should be noted that assessing the results of such studies is very difficult, since stress almost naturally occurs secondary to hair loss. Patients with circular alopecia develop an inferiority complex, a tendency to introspection and a need for constant encouragement. This condition is referred to in psychiatric practice as dysmorphophobia, that is, the fear of losing one's usual appearance, which should be taken into account when prescribing therapy.
2. Infection. There are known cases of circular alopecia after acute infectious diseases. Many, mainly domestic, scientists also recognize the role of foci of chronic infection (carious teeth, periapical granulomas, sinusitis, frontal sinusitis, otitis, etc.). However, there is still no reliable data indicating that their combination with circular alopecia is not accidental.
3. Physical trauma, like infection, can be a potential cause of disease. When exposed to physical stress, cells can produce heat shock proteins, which play an important role in the development of the immune response.
4. Genetic factors. The incidence of circular alopecia in family history is 4-27%. There are reports of circular alopecia in twins, with some pairs developing the disease at the same time. An autosomal dominant inheritance pattern with variable penetrance of the gene is suggested. The role of racial differences cannot be ruled out: circular alopecia is a common disease among the Japanese who inhabit the Hawaiian Islands.

The combination of circular alopecia with diseases of the atopic circle (atopic dermatitis, bronchial asthma) has been studied since 1948. The frequency of this combination, according to different authors, ranges from 1% to 52.4%. Japanese doctor T. Iked identified 4 types of circular alopecia, among which the atopic type is the most unfavorable, leading to total baldness in 75% of cases.

Studies of associations of alopecia areata with genes of the major histocompatibility complex (HLA), as well as the results of a study of polymorphism of genes of interleukin 1 receptor antagonists, indicate the genetic heterogeneity of this disease, which may explain the clinical polymorphism of alopecia areata, which is well known to physicians.

Pathogenesis of circular alopecia

Most clinicians support the hypothesis of the autoimmune nature of circular alopecia. The search for arguments confirming the hypothesis is conducted in three directions: identifying combinations with autoimmune diseases, studying the humoral and cellular links of immunity.

Combination with autoimmune diseases. Most often, there are descriptions of a combination of circular alopecia with thyroid diseases, however, the figures characterizing its frequency vary widely (8-28%). There are numerous reports of cases of a combination of circular alopecia with pernicious anemia, vitiligo, systemic lupus erythematosus, scleroderma, rheumatoid arthritis, autoimmune pathology of the testicles and many other diseases of an autoimmune nature.

It is known that patients with Down syndrome are susceptible to various autoimmune diseases. Circular alopecia in these patients is 60 times more common than in other mentally retarded people. Almost half of patients with Down syndrome experience total or universal alopecia.

Humoral immunity status. The study of various organ-specific autoantibodies has yielded contradictory results, which can be explained by both the comparative small number of patients examined and differences in the examination methods. Thus, antibodies to the microsomal structures of the thyroid gland, smooth muscles, parietal cells of the stomach, antinuclear antibodies and rheumatoid factor were detected in the serum of patients with circular alopecia. It is appropriate to recall that a low level of autoantibodies that do not have any damaging effect is considered normal and is found in most people.

The first direct indications of the possibility of autoimmune mechanisms of alopecia areata have been studied in recent years with the emergence of new facts indicating the presence of autoantibodies to hair follicles in 90-100% of patients with alopecia areata, and the level of detected antibodies was significantly higher than in the control.

Moreover, various IgM and IgG autoantibodies to several hair follicle antigens were detected.

State of cellular immunity. Contradictory data have also been obtained in the study of the cellular link of immunity. The total number of circulating T-cells is characterized as decreased or normal; the number of T-suppressors is characterized as decreased, normal, and even increased. Various functional disorders of T-lymphocytes are also revealed.

Direct evidence of the autoimmune genesis of circular alopecia is the detection of lymphocytic infiltrates within and around the hair follicle, as well as Langerhans cell clusters in the peribulbar area. When treating patients with contact allergens or minoxidil, the number of T cells in the peribulbar area decreases with hair regrowth, and remains the same if therapy is ineffective.

Attempts to detect antibodies against follicle components in the scalp have been unsuccessful.

In active lesions of circular alopecia, expression of HLA-DR antigens has been detected on epithelial cells of the precortical matrix and hair sheath; this is considered as a mechanism by which cells present their specific surface antigens to sensitized T-inducers.

Thus, circular alopecia appears to belong to the group of organ-specific autoimmune diseases, as evidenced by hereditary predisposition, increased frequency of organ-specific antibodies and disturbances in T-cell regulation of the immune response. However, since the antigen of interest has not been identified, it remains unclear whether normal hair components (melanocyte, x-ray, papilla cells) are affected or the immune system reacts to previously damaged hair follicle tissue. In addition, unlike most autoimmune diseases, no antibodies against follicle components in the scalp have been identified in circular alopecia to date. The search for such evidence is extremely promising.

If such evidence is presented, alopecia areata would be unique among autoimmune diseases in that it involves non-destructive changes in the target organ.

It should be mentioned that a small number of dermatologists dispute the autoimmune genesis of circular alopecia, without denying the immune mechanism of the disease. The basis for this opinion was the detection of genes encoding cytomegalovirus (CMV) in the skin of patients, while in healthy people, expression of these genes was not detected. The authors believe that the presence of CMV in hair follicles causes an immune response that leads to tissue damage. This hypothesis certainly needs proof, but the possibility of the origin of the target under the influence of an external source has not been refuted.

Pathophysiology and pathomorphology

It has been established that circular alopecia begins with the premature entry of follicles into the telogen phase in the center of the developing lesion, followed by centrifugal spread of the process in the form of a diverging wave. The ratio of anagen and telogen hairs varies widely depending on the stage and duration of the disease (normally A/T=9:11). As shown by the results of histological examination, in the early stage of circular alopecia, most follicles are in the telogen or late catagen phase; a few follicles in the anagen phase are located in the dermis at a higher level than normal. The development of the hair follicle in circular alopecia stops in the anagen III phase, when the internal root sheath takes a conical shape, and differentiated cortical cells do not show signs of keratinization. An exceptionally significant histological sign is the presence of a dense peribulbar intrafollicular lymphocytic infiltrate, more pronounced in the early stages of alopecia and consisting mainly of T cells and Langerhans cells. Sometimes the infiltrate also affects the upper, unchanged part of the hair follicle in the anagen or telogen phases. As mentioned above, the infiltrate resolves with the resumption of hair growth. The number of hair follicles in the formed lesion decreases. The secretory activity of the sebaceous glands decreases with an increase in the duration of the disease. Sometimes a long course of the disease leads to the death of the hair follicle and irreversible hair loss; in these cases, the pathogenetic mechanisms may coincide with those in pseudopelade. A histological examination of the affected skin helps to identify atrophic changes.

The abnormalities of the hair shaft structure characteristic of circular alopecia are well known. The pathognomonic feature is the exclamation point-shaped hair, which, however, is not always present. These are club-shaped hairs about 3 mm long. The distal end of these hairs is split; from the top of the hair, it thickens conically, the hair shaft is reduced in size, but is otherwise normal. When hair growth resumes, follicles producing several thin shafts are found.

A group of scientists led by A. Messenger made a significant contribution to the study of pathological changes in the follicle. It was shown that in the focus of circular alopecia in the anagen follicle, keratinocytes in the keratogenic zone are damaged. Using electron microscopy, the fact of non-specific damage to the matrix cells above the upper pole of the dermal papilla, as well as cells of the keratogenic zone, was established. Expression of HLA-DR antigens was detected in the cells of the precortical matrix and keratogenic zone, which allowed us to assume that these parts of the follicle are the primary target in circular alopecia. The authors proposed a hypothetical model explaining the formation of hair in the form of exclamation marks and the non-destructive nature of the disease.

The hypothesis is that, depending on the severity of the injury, follicles may respond in three different ways. Severe trauma damages and weakens the hair in the keratogenic zone, forcing the follicle to enter the catagen phase and then the telogen phase. These hairs break off when their keratogenic zone reaches the skin surface. These are the hairs that later resemble exclamation marks. Another follicle may enter the normal catagen phase and then the telogen phase in a timely manner and fall out with a normal club-shaped bulb. Such follicles produce dystrophic hairs in the new cycle. Finally, some follicles are probably damaged so little that, despite the occurrence of dystrophic changes, the anagen phase is not interrupted.

Symptoms and course of circular alopecia

The disease begins with the sudden appearance of a round bald spot, which is accidentally noticed either by the patient himself or (more often) by his relatives or hairdresser. Subjective sensations are usually absent, but some patients note increased sensitivity of the skin or paresthesia preceding the appearance of the lesion. The boundaries of the lesion are clear; the skin within it is smooth, without inflammation and peeling, sometimes of a doughy consistency and more easily gathered into folds than healthy skin; the mouths of the hair follicles are preserved. Sometimes, in the initial stage of alopecia, the skin is slightly hyperemic. Unlike pseudopelade, there is no skin atrophy and individual hair clumps in the center of the bald spot. In the progressive stage, healthy-looking hair along the edges of the lesion is easily epilated; the appearance of exclamation marks is characteristic. The further course of the disease is unpredictable. Sometimes, within a few months, hair growth in the lesion is completely restored. New foci may appear at different time intervals. Individual foci may quickly merge due to diffuse loss of hair separating them. Diffuse thinning of hair without formation of bald spots is possible. There are cases when the disease began with diffuse hair loss and led to total baldness within 2 days. Resolution of one foci may be combined with progressive hair loss in another foci. Collateral circular alopecia that developed after trauma has been described.

In 60% of cases, the first lesions appear on the scalp. Hair loss in the beard area is also possible, especially noticeable in dark-haired men. In many cases of circular alopecia, eyebrows and eyelashes fall out, sometimes this is the only manifestation of the disease. Partial or complete loss of vellus hair on the body and hair loss in the armpits and pubic areas are possible.

Gray hair in circular alopecia are usually not involved in the pathological process. If gray hair dominates, then with sudden loss of all pigmented hair, a false impression may be created that the person has turned gray in a few days. The newly growing hair is initially thin and devoid of pigment and only gradually acquires normal thickness and color. Tufts of growing gray hair resemble a picture of poliosis. The facts allowed us to assume that the target in circular alopecia is melanogenesis. Concerning the fate of the melanocytes themselves in the affected hair follicles, there are different opinions: some authors note their disappearance, others manage to detect them. Pigmentary disorders in the growing hair are probably explained by incomplete melanocytic activity in early anagen. It has been established that the activity of melanocytes correlates with the differentiation of cortical cells, and perhaps depends on it. It is believed that circular alopecia is a disease of differentiating cortical keratinocytes, therefore the follicle in the telogen phase is involved in the pathological process; this also explains the non-destructive nature of the disease.

Eye changes. Pigment formation disorders in circular alopecia may affect not only the melanocytes of the hair follicles, but also the pigment cells of the eyes (changes in the color of the iris from brown to blue; spotted atrophy of the retinal pigment epithelium, pigment hyperplasia, hyper- and hypopigmentation of the retina, etc.). Changes in the pigment system of the eyes in circular alopecia are similar to those in vitiligo. The relationship between circular alopecia and cataracts is debated.

Nail changes occur in 10-66% of patients with circular alopecia. Dystrophy of the nail plates can manifest itself in a variety of changes: punctate depressions, thinning and fragility, longitudinal striation, koilonychia (spoon-shaped concave nails), thickening of the nails, onycholysis (partial separation from the nail bed), onychomadesis (total separation from the nail bed).

Classification of circular alopecia

There is no single classification of the disease. Depending on the area of the lesion, the following clinical forms of circular alopecia are distinguished.

Focal alopecia is characterized by the appearance of one or more large, up to several cm in diameter, bald spots on the scalp or in the beard growth area. Within a few months, hair growth in the lesion(s) can be completely restored. If the disease progresses unfavorably, focal alopecia can develop into subtotal, total, and universal forms.

Subtotal alopecia is diagnosed when small areas of hair growth remain on the scalp; total alopecia is characterized by a complete absence of hair on the scalp. Universal (malignant) alopecia is characterized by the absence of hair in all areas of hair growth.

It is obvious that the given classification lacks quantitative parameters for assessing the area of damage, which significantly complicates the comparative assessment of the published clinical data. Filling this obvious gap, American dermatologists with many years of experience in studying the problem (Olsen E. et al.) proposed criteria for quantitative assessment of the degree of baldness. The authors focus on the condition of terminal hair on the scalp, taking into account the main clinical forms of the disease (focal, total, universal).

Several methods have been proposed to assess the area of baldness:

1. Mentally divide the scalp into 4 quadrants. Calculate the total area of baldness as a percentage. The area of each quadrant is 25% of the scalp area.
2. If the total area of all areas is 100%. For example, if hair is missing on 1/4 (25%) of the back of the head, from the area of the entire scalp z is 0.25 x 24% = 6%. If the same patient has a second bald spot on 40% of the crown, this will be equal to 0.4 x 40% = 16% of the scalp area. Thus, the total area of baldness in this patient is 6% + 16% = 22% of the scalp area, or S, according to the proposed classification.
3. In subtotal alopecia, it is easier to estimate the scalp area with remaining hair. For example, hair growth is preserved on 8% of the scalp area; therefore, the total area of the bald spot is 92% (S4a).
4. It is also easy to draw lesions on a diagram; this method makes it easier to document the location and size of lesions. If the lesions are numerous and scattered, it is convenient to use an image analyzer to determine the area of the lesion.

Each physician is free to use the method that seems most convenient to him, but the chosen method should become the standard for assessing the degree of scalp damage in all patients in a given study.

S (scalp). Hair loss on the scalp.

• S0 = hair preserved
• S1 = 25% hair loss
• S2 = 26%-50% hair loss
• S3 = 51%-75% hair loss
• S4 = 76%-99% hair loss
  • Sa = 76%-95% hair loss
  • Sb = 96%-99% hair loss
• S5 = 100% hair loss

B (body). Hair loss in other areas of the body.

• B0 = hair preserved
• B1 = partial hair loss
• B2 = 100% hair loss

N (nail). Changes in the nail plates.

• N0 = absent
• N1 = partially modified
• a = dystrophy/trachyonychia of all 20 nail plates

Terminology:

Alopecia totalis (AT) = S5B0

Alopecia totalis/alopecia universalis (AT/AU) = S5 B0-2. The term is recommended for use in cases of total alopecia, accompanied by partial hair loss on the trunk.

Alopecia universalis (AU) = S5B2.

In case of subtotal alopecia of the scalp, as well as in the presence of foci of loss of vellus or bristly hair, the terms AT, AT/AU and AU are not used.

According to the authors of the classification, the use of the given standards will make the assessment of clinical data more objective, which will facilitate the cooperation of doctors studying the problem of circular alopecia.

In addition to the forms of the disease, characterized by the area (and, consequently, the severity) of the lesion, there are two more clinical varieties of circular alopecia:

Ophiasis (snake-like, ribbon-like form) is manifested by hair loss in the occipital region and the spread of the lesion along the periphery of the scalp to the auricles and temples. This form of alopecia is often combined with an atonic state and is very torpid to the therapy.

The point (reticular, pseudosyphilitic) form of the disease is characterized by the appearance of a network of small, several mm in diameter, contacting foci of hair loss, scattered over different areas of the head. Like the previous one, this form of circular alopecia is prognostically unfavorable.

Of great interest is the pathogenetic classification (T. Ikeda), which takes into account the concomitant clinical pathology and prognosis of the disease. The author identifies 4 main types of circular alopecia (the frequency of cases typical for Japan is given).

• Type I. Common type. Characterized by the appearance of round bald spots. Occurs in 83% of patients, occurs mainly between the ages of 20 and 40, and ends in less than 3 years. In some spots, hair grows back in the first 6 months. Total alopecia develops in only 6% of cases.
• Type II. Atopic type, occurring in 10% of patients. The disease occurs in children suffering from bronchial asthma, atopic dermatitis or pollinosis, and is characterized by a mesh pattern of hair loss or the appearance of individual rounded foci. Individual foci usually persist for more than a year. The total duration of the disease is up to 10 years or more. Total alopecia occurs in 75% of patients.
• Type III. Prehypertensive type (4%) occurs mainly in young people whose parents suffer from hypertension. It is characterized by a rapid progression, a mesh pattern of hair loss. The incidence of total alopecia is 39%.
• Type IV. Mixed type (3%); age of onset of the disease is over 40 years, the course is long, but it develops into total alopecia only in 10% of cases.

In general, this classification was approved by scientists from a number of countries, although the author’s identification of a prehypertensive type of the disease did not find support.

Thus, circular alopecia is characterized by a variety of clinical forms in combination with inherited and autoimmune pathology, infectious diseases; the role of environmental factors cannot be ruled out.

Despite the unpredictability of the course of circular alopecia, it can be argued that the prognosis of the disease is worse when it occurs in the prepubertal period, especially in the presence of atopy, with ophiasis, and also with the detection of high titers of antibodies to components of the thyroid gland and leukocyte nuclei. Although the initial occurrence of circular alopecia is not associated with atrophy of hair follicles, the long-term course of the disease can gradually lead to dystrophic changes in the follicles and their death. This process, as with pseudopelade, is not accompanied by visible inflammation of the skin. Histological examination helps to identify the formed atrophic changes.

Diagnosis of circular alopecia

Diagnosis of circular alopecia is usually not difficult. During examination, it is necessary to make sure that there is no inflammatory erythema, flaking, atrophy, telangiectasias and other skin changes. The diagnosis can be verified by examining the hair, which in the progressive stage is easily epilated from the area surrounding the bald spot. In the area of loose hair, telogen and dystrophic hair are found, as well as hair in the form of an exclamation mark, which are easily identified when examined with a magnifying glass or under a microscope at low magnification.

It is also necessary to examine the area of growth of the beard, moustache, eyebrows, eyelashes and the entire skin to detect foci of circular alopecia that have remained unnoticed by the patient. Attention should be paid to the condition of the nails, since their dystrophic changes are considered a prognostically unfavorable sign.

Considering that the success of treatment depends on how fully the probable etiological and pathogenetic factors are identified and corrected, a patient with circular alopecia should be carefully examined.

Particular attention should be paid to finding foci of chronic infection, primarily odontogenic and ENT organs, for which X-ray diagnostic methods are used (orthopantomogram, X-ray of the paranasal sinuses). Ultrasound of the abdominal organs and, in women, the pelvis is also necessary. The examination and evaluation of the results are carried out with the participation of specialists in the relevant field.

To identify other intercurrent diseases and disorders, it is necessary to evaluate the hemogram, biochemical blood parameters, coagulogram, thyroid and adrenal cortex metabolites, immune status, sella turcica X-ray, EEG. Many patients need to consult an endocrinologist, and women - a gynecologist-endocrinologist.

Differential diagnostics

First of all, it is necessary to exclude cicatricial alopecia, or pseudopelade condition, which is the final symptom of a number of skin diseases on the scalp. The skin surface in the areas of baldness in pseudopelade is smooth, white, shiny, without skin pattern and mouths of hair follicles. Atrophied areas are somewhat sunken, not compacted. Individual hairs or tufts of hair may remain within the foci.

Mycosis of the scalp should be excluded in the presence of flaking, hyperemia, broken hairs (including low broken ones - "blackheads"), infiltration and cicatricial focal alopecia. For this purpose, examination under a mercury-quartz lamp with a Wood filter and mycological examination of the altered hair and scales are used.

The presence of a large number of small, 1-1.5 cm in diameter, irregularly shaped foci of hair thinning, reminiscent of "moth-eaten fur" should suggest secondary syphilis; in such cases, it is necessary to look for other clinical manifestations of this disease and conduct a serological blood test.

Trichotillomania - a neurotic condition in which the patient pulls out his own hair - can present certain diagnostic difficulties. In trichotillomania, bald patches are of bizarre outlines, with uneven contours, with some hair remaining within them. Dystrophic hair and hair in the form of exclamation marks are absent, as is the zone of loose hair.

Acute diffuse hair loss with circular alopecia is difficult to differentiate from diffuse telogen effluvium, which occurs after taking a number of medications, X-ray therapy, poisoning with arsenic, mercury, etc. Hair cycle disorders can also develop as a result of infectious diseases accompanied by fever (above 39 °C), intoxication (secondary syphilis, HIV infection, etc.). The diagnosis of circular alopecia is confirmed by the presence of dystrophic hair and hair in the form of exclamation marks. In all cases of diffuse hair loss, serological testing is necessary to exclude syphilis and HIV infection.

Focal alopecia can be artificial and occur as a result of excessive hair stretching when curling hair with curlers, hot curling irons, pulling hair into a ponytail, etc.

Severe alopecia can develop with congenital dystrophies of the hair shaft (monilethrix, trichotortosis, etc.), which are detected at birth or develop during the first years of life. The correct diagnosis of these rare diseases is facilitated by anamnesis, detection of broken hairs and detection of shaft defects during careful microscopic examination. With circular alopecia, there are no changes in the hair shaft.

Treatment of circular alopecia

To this day, no universal, safe medicine has been found that would permanently rid the patient of circular alopecia.

Thus, reports of high efficiency of certain means in the treatment of the usual type of baldness (according to the classification of T. Ikeda) should be treated very critically, since even without treatment the disease is prone to independent remissions, and only 6% of patients develop total alopecia. At the same time, with the atopic type of circular alopecia, despite treatment, total alopecia occurs in 75% of patients. Only stable success in the treatment of total and universal alopecia - traditionally resistant to therapy forms of circular alopecia - can testify to the real efficiency of the used means.

Experience shows that resistance to therapy and an unfavorable prognosis are possible under the following circumstances:

• family history of the disease
• concomitant atopic condition
• combination with autoimmune diseases
• onset of disease before puberty
• frequent relapses
• ophiasis, total and universal forms of circular alopecia
• combination with severe dystrophic damage to the nail plates
• loss of newly growing vellus hair

Therapy should be comprehensive and as individual as possible. Treatment should be preceded by a thorough examination of the patient in order to identify and correct concomitant diseases and background disorders (foci of infection; psychogenic factors; neurotransmitter, microcirculatory and hemorheological changes; hyperthermia-hydrocephalic syndrome, etc.).

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