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Alopecia androgenetic
Last reviewed: 17.10.2021
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[Pathogenesis
The role of androgens in the development of normal alopecia is universally recognized. The second factor of pathogenesis is a genetic predisposition (androgen-sensitive follicles). The third is the change in the balance of enzymes involved in the metabolism of androgens. Enzyme 5-alpha-reductase catalyzes the conversion of testosterone to dihydrotestosterone. As a result of the contact of dihydrotestosterone with the follicle receptors, the process of gradual miniaturization of the hair is included. Enzyme aromatase performs the conversion of androgens to estrogens, which have an antiandrogenic effect. You can not also exclude the role of living conditions, the nature of nutrition and other factors that accelerate the aging process of the whole organism.
Pathomorphology
In the area of alopecia, most follicles are short, reduced in size.
Symptoms of androgenetic alopecia
The main clinical sign is the change of terminal hair more thin, short and less pigmented. The process is accompanied by a shortening of the anagen phase and, correspondingly, an increase in the amount of hair in the telogen phase. Some follicles are delayed with entry into the anagen phase, their mouths look empty.
In men, baldness begins with a change in the hairline area, the forehead becomes taller. Gradually deepening the bitempolar bald patches, there is a thinning of hair, and then a bald patch in the parietal region. In the lateral and posterior regions of the scalp, the hair is retained (androgen-resistant follicles)
In women, the frontal line of hair growth usually does not change, there is a diffuse hair thinning in the fronto-parietal region, the character of the expansion of the central part. The rate of these changes is increased when taking progesterone-dominant contraceptives and after the onset of menopause. Women with rapid progression of alopecia, as well as with the gradual onset of alopecia combined with dysmenorrhea, hirsutism and acne, need to be examined to determine the cause of hyperandrogenism.
It has long been seen the connection of ordinary baldness and seborrhea, which is reflected in the use of the term "seborrheic alopecia" as a synonym for normal alopecia. It is known that the amount of excreted fat is also controlled by dihydrotestosterone.
Diagnostics
An objective method of diagnosing normal alopecia is a trichogram - microscopic examination of distant hair. In the fronto-parietal region, an increased amount of hair is detected in the telogen phase and, correspondingly, an anagen / telogen index decrease (normally at 9: 1); there are also dystrophic hair.
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Treatment of androgenetic alopecia
Treatment of androgenetic alopecia should be continued, the cessation of therapy leads to the resumption of hair loss. The treatment uses substances that suppress the effect of androgens either by inhibiting the activity of 5-alpha-reductase, or by blockade of androgen receptors in target tissues, or by increasing the production of globulin binding sexual hormones.
Among the effective means of external treatment should be noted lotions containing extracts of herbs with antiandrogenic action (Chronicity, Trichostim, 101G). In 30% of patients, a significant clinical improvement causes a 2% (5%) solution of a powerful vasodilator - minoxidil (Regaine et al.).
For the general treatment of common baldness in men finasteride is prescribed, an inhibitor of 5-alpha-reductase, at a dose of 1 mg per day (Propecia). In the general treatment of alopecia in women, cyproterone acetate is effective. Since the drug has an anti-estrogenic effect, simultaneous administration of estrogens is necessary. In this regard, deserve attention combined oral contraceptives - drugs Diane-35 and Silest. It should be remembered that systemic antiandrogens have serious side effects, so their purpose in order to prevent, in fact, a cosmetic defect should be carefully weighed.
In the case of pronounced baldness, the method of choice is a surgical correction, which consists in the transplantation of androgen-resistant follicles from areas of hair thinning or alopecia; while the patient should continue to use drugs that prevent the loss of preserved androgen-sensitive hair. Physiotherapeutic methods of treatment are used as auxiliary ones.