The same as male pattern hair loss (male pattern hair loss, MPHL) and female pattern hair loss (female pattern hair loss, FPHL) pathogenesis, clinical manifestations, but it eventually led to a significantly different. Currently, the pathogenesis of male pattern and female pattern hair loss is not yet fully clear, especially existing theories still can not explain why the same pathogenesis, different gender friends have different hair types of hair loss. Thus, the pathogenesis of male pattern and female pattern hair loss remains to be further studied. Many existing clinical treatment of "some fat friends" have a certain effect.
To understand the whole process of hair Hair Extensions loss, it is necessary for the normal growth of hair have a comprehensive understanding. Hair growth is affected by many factors (change anagen, catagen and telogen) its growth rate and the growth cycle and eyebrows and eyelashes, and other parts of the body other special hair growth are regulated by a number of key factors, At present, our understanding of these factors is still very superficial. Depth exploration of factors and their interaction with the corresponding receptor among these, not only conducive to elucidate the pathogenesis of this disease, but also to find more therapeutic targets to further develop a more effective treatment.
Treatment of alopecia new drugs emerging, which also allows us to pathological, physiological levels for a more comprehensive understanding of hair loss. Different professional clinicians, need to understand the etiology and treatment of hair loss and want to send the Friends necessary publicity and education, especially education fat friends how reasonable treatment options, it is very important. Previous studies reported significantly underestimated the incidence of hair loss, hair loss treatment is the key to early drug use as much as possible to prevent further development of hair loss, hair loss and therefore underestimate the incidence is an urgent need to address the problem. In addition, underestimate the incidence of alopecia hair loss will impact on the diagnosis and treatment of resources invested.
Used to describe the male pattern baldness and female pattern hair loss has not been possible unified terminology, androgenetic alopecia (androgenic alopecia, AGA) is more appropriate for men hair friends, because large amounts of data confirmed that the male androgen and genetic susceptibility to Friends of the combined effects lead to male hair with characteristic hair loss. But in the female fat friend, the other may play a major role in the pathogenesis, so the term androgenetic alopecia hair is less suitable for women friends.
■ Male pattern baldness:
As androgenetic alopecia literally suggests, the combined effects of androgens and genetic factors led to the clinical characteristics of hair loss. In fact, it has been found in the androgen receptor gene and male pattern hair loss showed a significant positive correlation. Friends generally considered male hair pattern hair loss is consistent with their grandfather, but this view is not correct. Existing research shows that men send their friends maternal and paternal genes are related, autosomal dominant and (or) polygenic.
In addition, male pattern baldness penetrance is not constant. Therefore, almost by the genetic background of the family is difficult to accurately predict whether a particular hair alopecia occurs in the future of Friends. Obviously, if there is no inherent genetic susceptibility, regardless of how changes in androgen levels, hair loss does not occur. Perhaps in the near future, may be based on other factors, such as receptors or specificity of male pattern hair loss in patients with genetic subtype classification, which could achieve the purpose of a more accurate classification.
Topical minoxidil is a potassium channel opener and vasodilator drugs, the study found the drug for male pattern hair loss have a therapeutic effect. However, the role of potassium channels and vasodilation in the hair loss is no clear conclusion.
■ androgens in male pattern baldness Role
The role of androgens in male pattern hair loss in the first through the study of testicular castration's been confirmed. Castrated male pattern hair loss who do not happen, but given androgen replacement therapy after androgenic alopecia can occur. With male pattern baldness is the most directly related to DHT (dihydrotestosterone, DHT), which is through the study of a family from the Dominican Republic concluded, in the absence of male family type Ⅱ 5α-reductase (type Ⅱ 5α-reductase, 5RA), and therefore the body does not contain DHT, which led to them in addition to the major phenotypic abnormalities in male pattern hair loss never happened. Finasteride is a competitive type Ⅱ 5α-reductase inhibitors, can reduce the level of DHT in the body, can be clinically effective in the treatment of male pattern baldness, which is also confirmed from another aspect of DHT in male pattern hair loss in effect.
The role of androgen in the hair from the peripheral blood circulating testosterone, testosterone is mainly produced by the adrenal glands and testes (Note). More than 97% of circulating plasma testosterone-binding protein (such as albumin, testosterone and specific corticosteroid binding globulin) binding of these binding testosterone no biological activity. Not bound to plasma protein binding of passive diffusion of free testosterone to the skin cells, thus catalyzed 5α-reductase into DHT, which is significantly higher than the activity of testosterone. (Note: The female body mainly from the ovarian androgen testosterone, followed by the adrenal glands)
5α-reductase isoenzymes are two, namely 5α-reductase type Ⅰ and type II 5α-reductase. 5α-reductase type Ⅰ mainly present in hair Human Hair Wigs follicles and sebaceous glands sebaceous units, type II 5α-reductase is mainly present in the outer root sheath of hair follicles, prostate and dermal papilla.
Cytoplasmic androgen receptor protein is generally combined with the A state, when it released protein A, and the formation of dihydrotestosterone dihydrotestosterone - androgen receptor complex, the complex is transported to the nucleus. DHT-induced androgen receptor conformational changes, so that the androgen receptor and DNA binding, and then cell-specific transcription of mRNA, and further translation of specific proteins that act on the hair follicles, so hair follicles inactivation. In the above process, there are many alternative ways. Testosterone can bypass 5α-reductase cells in the blood circulation was converted into dihydrotestosterone, and then enter the cell. Testosterone - form a protein complex into the nucleus and induce mRNA production. In addition, other androgens, such as DHEA can also be converted directly into cells and dihydrotestosterone. These bypass explain why some friends in the treatment of hair can not achieve the desired effect. One or more aspects of the treatment of male pattern baldness many drugs are in the conversion process and the role of androgen pathway as a blocking target. After puberty, some of androgens including DHEA, including not play a physiological function, so you can be blocked directly.
Aromatase enzyme adenylate cyclase and also plays an important role, because these enzymes and the lower levels of cyclic AMP, and 5α-dihydrotestosterone levels will rise reductase, hair growth may slow down. Unfortunately, there is no in-depth study in this regard, the specific role of these enzymes has not yet been elucidated. This may explain why some men Fat Friends poor use of non-therapeutic effects that finasteride's.
DHT enables terminal hair follicle miniaturization manner. In the subsequent hair cycle, tapering hair, hair color gradually fades. And because growing progressively shorter hair gradually becomes shorter. This process may take years or even decades, but typically characterized by hair gradually turned into vellus hair, eventually these vellus hair loss, hair follicles shrink disappear, leaving only smooth scalp.
Note: The key step in the metabolism of androgens
1, testosterone (T) combined cycle binding globulin (G).
2, T into the target cells.
3, T converted to dihydrotestosterone (DHT).
4, DHT binding the androgen receptor (AR) within the cell.
5, DHT-AR complex into the nucleus.
6, DHT-AR complex binds DNA, produced in the cell-specific mRNA.
7, protein synthesis, resulting in physiological effects.
8, T AR can also be combined directly with a cell cytoplasm.
9, T-AR complex into the nucleus.
10 A combined androgen engage in the cytoplasm of AR.
■ female pattern hair loss:
The exact cause of female pattern hair loss is not yet clear. The vast majority of female pattern hair loss hair friendly application finasteride treatment failure, indicating that female pattern hair loss may be unrelated to dihydrotestosterone.
Although there may be some subgroups of women suffering from hair Friends of hyperandrogenism, they exhibit a characteristic of hair loss, its clinical manifestations are often similar to male pattern baldness, the hair Friends may therefore effective against androgen therapy; But they Women account for only a small portion of hair loss.
Because the lack of a clear understanding of the pathogenesis of female pattern hair loss, the treatment of the symptoms of clinical experience and more traditional methods (Note) based rather than a scientific theory. Overall, female pattern hair loss is a symptom of the pathogenesis unclear, the therapeutic effect of minoxidil is certain, but the mechanism is not fully understood. Other treatments, such as female androgen excess, then take the anti-androgen therapy include spironolactone and flutamide, etc. (Note: flutamide would cause serious damage to the liver, and then not), are not based on proven concept.
Note: The treatment of female pattern hair loss (PHLA)
◆ careful physical examination, including hair and hair pull test image checking.
◆ conduct laboratory tests to rule out endocrine disorders, iron deficiency, lupus and other systemic diseases.
◆ if necessary scalp biopsy to rule out alopecia areata, telogen effluvium, inflammatory scarring alopecia, or hair loss.
◆ First, the use of minoxidil topical treatment.
◆ Consider vitamin therapy, including biotin (vitamin H) and folic acid.
◆ If appropriate, consider hair transplant surgery.
■ Treatment Overview
So far, has been proven to male pattern and female pattern hair loss is only effective drugs into two categories, one is directly promote hair growth drug, the other is metabolic pathways affecting androgen drugs (Note). In both types of drugs are their only one drug approved by the U.S. Food and Drug Administration (FDA), and they are Minoxidil and Finasteride.
Minoxidil
Minoxidil is a potassium channel opener drugs and vasodilators, was originally used to treat high blood pressure and found it is an important cause of adverse reactions in the process of hirsutism treatment of hypertension. In a study for the treatment of male pattern hair loss, the hair counts were significantly higher in the treatment group, but security is very high, after FDA approval in 1988 topical minoxidil 2% solution can be used to treat male pattern baldness and female pattern hair loss in non-prescription drugs (OTC drugs). In 1997, FDA approved 5% minoxidil solution of OTC drugs for the treatment of hair loss.
Initially considered topical minoxidil by dilation of blood vessels to promote hair growth, it does not seem correct. Because there is no blood supply to the tissue culture medium, minoxidil still possible to improve the survival rate of the hair Lace Wigs. Now that Minoxidil is a non-specific drugs to promote hair growth, but its mechanism is not entirely clear.
An ongoing 48-week randomized double-blind multicenter trial (double-blind trial, refers to the testing process, the test is the test and those who do not know who belongs to the tested group [experimental group or a control group], When analyzing the data analyst, usually do not know the data is being analyzed belong to which group). For 5% and 2% minoxidil solution in the role of male pattern hair loss and safety were studied.
It was found that 5% minoxidil was significantly better than 2% minoxidil and control groups. 5% minoxidil group, hair growth ahead. Friends of female pattern hair loss hair is concerned, after more than 32 weeks in a clinical trial, the use of 2 percent minoxidil solution, hair count and hair weighing an increase of 29% and 42%, respectively, while the control group increased -2.6% and 1.9%. In the suspension of 2% and 5% minoxidil treatment, hair counts at 24 weeks and weighing returned to control levels. Few adverse drug reaction, 5% minoxidil treatment group, only 6% fat friends irritant contact dermatitis and dermatitis, and 2% minoxidil group rate was only 2%. In females, the 2% minoxidil treatment groups in the incidence of facial hirsutism 3% to 5%, and 5% minoxidil group to be slightly more.
Minoxidil solution, is the Friends of male pattern hair loss hair hair transplant surgery as a supplementary drug. For most accepted hair transplant hair friendly, the topical application of 2% minoxidil solution can reduce postoperative hair loss, hair transplantation shorten time to start re-growing. Many have experienced hair transplant physicians will recommend to patients using minoxidil.
Note: to promote hair growth drugs and their mechanism of action:
Minoxidil use:
Men should use 5% minoxidil solution, instead of 2 percent minoxidil solution, unless it is because of a bad reaction to be exchanged (Note). Women should use concentration of 2% in order to reduce adverse reactions, particularly hirsutism. Use 2 times a day can play the best effect, do not use just one second. Use drip drug applied to the scalp, rather than using spray sprayed on the hair or scalp. (柆 柆 he has been with the nozzle, the very good way). Some scholars are working on a matrix of excipients foam minoxidil topical formulations (Note: There are already Rogaine foam).
NOTE: Application Notes minoxidil
◆ Men concentration of 5%.
◆ Women with 2% concentration (Note: 2% effect is not obvious Dr. Lei Demeng suggested by early evening with a 2% to 5%.)
◆ Use 2 times a day, in order to achieve the best results.
◆ drugs to smear on the scalp, but do not spray onto the hair.
◆ entire site to be applied thinning hair, hair loss, not just parts of the hair.
◆ When using the first liquid dripping on the scalp, rather than using spray bottle with a spray device. (柆 柆 on the use of sprinklers)
◆ If scalp irritation, to referral immediately.
◆ start 4-8 weeks medication may increase the phenomenon of hair loss, hair should inform friends, do not stress, should continue medication.
■ androgen action:
Blocking sites of action of androgens, so far only two drugs have been proven to be effective, namely: 5α-reductase inhibitors and androgen receptor competitive antagonist (Note). Thus, the concentration of drug in more categories.
■ 5α-reductase inhibitors
There are two 5α-reductase isoenzymes one, namely type I 5α-reductase type II 5α-reductase and. Type I 5α-reductase is present in all body tissues, including skin, kidney, liver, and brain; Type II 5α-reductase is mainly present in scalp hair follicles, prostate and liver. Both enzymes can be converted to dihydrotestosterone testosterone for men with a genetic susceptibility in terms of hormone dihydrotestosterone is an important cause of male pattern hair loss.
■ Finasteride
Finasteride is a type Ⅱ 5α-reductase competitive inhibitor, for the treatment of male pattern hair loss effectively. Oral dosage of 1mg / d. In a clinical trial, a total of 1553 cases of 18-41 year-old patients with male pattern hair loss finasteride and placebo treatment found that finasteride can not only inhibit the progression of hair loss, but also to promote hair growth. These patients subsequently followed up for five years to evaluate long-term efficacy of finasteride and safety. Evaluation indicators include top of the head hair count, patient questionnaires, the investigator's assessment and evaluation of the scalp spherical photography.
The results show that the assessment on the above indicators, the finasteride group were significantly superior to placebo. Long-term safety assessment also shows that finasteride relatively safe, drug group, only 0.3% of patients with loss of libido or erectile dysfunction. The average content of finasteride in semen was 0.26ng/ml, the highest content of 1.52ng/ml, far below the level that can affect the fetus. No other reported adverse reactions and interactions between drugs. In another randomized double-blind controlled study, 424 cases of male patients to participate in trials, treatment for 24 months, showed that finasteride finasteride certainly greater efficacy in patients 41 to 60 years old male. Spherical photography scalp treatment group, the patient's self-assessment and investigator assessment was superior to the control group. Many aspects of sexual function adverse reactions occurred in this age group, the rate was 8.7% in the treatment group, the control group was 5.1%. Further analysis also found that, compared with the 41-50 age group, 51 patients-60 age group that patients taking a higher incidence of non-finasteride after the suppression of sexual function.
A study of the efficacy of finasteride for more convincing, is a double-blind trial nine pairs of monozygotic twins, the course of 12 months. The results on the scalp spherical photography, hair count and patient self-assessment and other indicators, the treatment group were significantly better than placebo.
Since finasteride in serum prostate-specific antigen (prostate-specific antigen, PSA) levels by 30% -50%, it is recommended for more than 40 years old male patient taking finasteride finasteride to consider PSA levels will reduce ( medication instructions specified). However, the above correction is not very accurate, there may be corrected too high or too low, can sometimes lead to diagnostic errors. Therefore, high-risk groups, should be monitored PSA levels.
Non-use of finasteride for:
Finasteride can effectively prevent the progression of hair loss, thinning hair once so patients should be started as soon as possible (note). Finasteride is best suited for male patients 18 to 41 years before the occurrence of mild to moderate scalp hair loss, but also widely used in male patients 41 years or older. It should be emphasized three key questions:
① Application finasteride hair density did not change after finasteride treatment does not mean treatment failure, as long as no progress progressive hair loss that hair loss is not worsening, it means that the treatment has been effective because the treatment of androgenic alopecia is not , the degree of hair loss will continue to develop;
② lack of effective communication between patients and physicians is the main reason the patient can not insist on taking finasteride non;
③ Although women should not use finasteride, should not have been broken or crushed touch finasteride tablets, but women semen of men taking the drug exposure on fetal development is not dangerous. Not recommended for female patients taking finasteride, pregnant women or women of childbearing age disabled because finasteride can cause fetal male external genitalia malformations, such as hypospadias and feminization of male genitalia. ( Note: especially disabled women of childbearing age, fear of unintended pregnancy affect the fetus without further except fertility.)
Note: The application of non Note Finasteride is:
◆ Once hair loss, early applications.
◆ medication before the first part of the photo shoot a hair for future comparative efficacy.
◆ hair density did not change after a period of treatment, said treatment is effective, but not invalid.
◆ change every physician referral told libido.
◆ If you really need to, you can send friends to sildenafil (sildenafil, sildenafil), tadalafil (tadalafil), or vardenafil (vardenafil), etc. in order to increase sexual function, but generally rarely necessary.
◆ Women Do not touch the broken finasteride tablets.
◆ women without finasteride. (However, women can no longer take birth)
◆ Women taking the drug exposure of male semen is not dangerous for the fetus.
■ Dutasteride
Dutasteride is an effective inhibitor of type I and type II 5α-reductase. As a dual 5α-reductase inhibitor, dutasteride can effectively reduce serum dihydrotestosterone. 2002 Dutasteride was approved by the U.S. FDA for the treatment of benign prostatic hyperplasia, but used in the treatment of hair loss do not have enough experience. Of the recommended dose of dutasteride (0.5 mg / dl) in serum dihydrotestosterone reduced by 90%, while the recommended dose of finasteride (1 mg / dl) can only make a 70% reduction in serum dihydrotestosterone. In pharmacology, dutasteride is more effective than finasteride, but also a lack of long-term and effective in clinical trials to prove its treatment of benign prostatic hyperplasia and male pattern baldness in rats.
Dutasteride treatment of male pattern baldness security has not been confirmed. There is no one model can be used to type I and type Ⅱ 5α-reductase blocked. Type I 5α-reductase function is not entirely clear, there can not prove whether it would have adverse effects after being blocked. In fact, the brain tissue type Ⅱ 5α-reductase deficiency, but whether children or adults, have expressed throughout the brain tissue type I 5α-reductase, which shows that type I 5α-reductase may have important functions unrelated to sex such as catabolism of neuroactive steroid synthesis or neurotoxic steroids. The researchers also found that the level of human tissue-type I 5α-reductase breast cancer tumor size was negatively correlated, suggesting that growth for this common malignancy may have inhibited.
Pharmacological studies have shown that the half-life of dutasteride over 240h, instead of finasteride is only 6 ~ 8h. Dutasteride long half-life, adverse reactions and therefore it can be imagined. If used to treat male pattern hair loss, it is necessary to fully consider the adverse effects that may arise. (Note: The product name "AFT" (0.5mg dutasteride), produced by GlaxoSmithKline, UK, November 2011 to enter the Chinese Dr. Lei Demeng book published in 2005 also mentioned dutasteride. stronger medicine capsules, in "5α-reductase inhibitors" that section, but 2012 U.S. FDA drug safety information warns new study found that "Dutasteride" would increase the risk of prostate cancer in men!)
■ System androgen receptor blockers:
Cyproterone, (Note: color Pronk, special expensive) is a potent anti-androgen drugs, and androgen receptor with high affinity by binding to the androgen dihydrotestosterone receptor competitive role (Figure BU 1, Step 10). Cyproterone acetate is approved for use in Europe for the treatment of female pattern hair Curl Machine loss have a certain effect, especially for those with high levels of serum ferritin in patients with female pattern hair loss. Compared with minoxidil, cyproterone of female patients with "hyperandrogenism" particularly effective in the clinical manifestations, including female hyperandrogenism signs of acne, hirsutism, menstrual disorders, and high body weight. Potential adverse reactions include cyproterone main cause menstrual disorders, weight gain and breast pain, while also making the feminization of the male fetus, so women of childbearing age in the application must be long-term use of cyproterone treatment of female pattern hair loss pill . (If spironolactone invalid female hyperandrogenism, cyproterone effective but cyproterone been approved by the FDA. Cyproterone and Diane 35 is generally used together)
Flutamide, is a non-steroid anti-androgen drugs, oral dose of 250 mg / d. In clinical trials hyperandrogenism female hair loss in patients with a 48 cases, the test is divided into 50mg cyproterone group, 5mg finasteride group, 250mg flutamide group and control group 4 group, continuing medication for 1 year . The results showed that, compared to the group with the blank, flutamide group of patients Ludwig score decreased by 21%, rather than the finasteride group and cyproterone group Ludwig score did not change. (Note: that flutamide flutamide, said Dr. flutamide has been confirmed will cause severe damage to the liver, should no longer apply)
Spironolactone is a potassium-sparing diuretic, has anti-androgenic effect, also proved to be effective for female pattern hair loss. Anti-androgen spironolactone weak (Note: For the purposes of hyperandrogenism), require long-term and high-dose use in order to take effect. Female pattern hair loss treatment is recommended when using a dose of 100 to 200 mg / d, but even with this dose, it can only inhibit the progression of hair loss, and can not increase hair density. Spironolactone can cause menstrual disorders and feminized male fetus, so women of childbearing age need while taking the pill. Hyperkalemia can also occur during treatment, so patients need to understand the basis of the electrolyte level and monthly monitoring, while avoiding potassium intake, these are very important.
■ topical androgen receptor blockers:
Development of topical anti-androgen drugs has been a problem, people have been committed to the androgen receptor in the development of a potent topical application of inhibitors, thus avoiding systemic adverse reactions caused. Sovak recently reported a new fluridil compounds (Note: fluorine Rhodia Seoul), with a topical anti-androgen effect, but not systemic absorption. In a prospective study of a period of three months, the number of male pattern hair loss in patients with 2% fluridil or placebo indicators evaluated include hair photos and blood tests. The results showed that accepts 2% fluridil treated patients, the proportion of hair growing from 76% to 85% before treatment (medication for 3 months) and 87% (medication nine months), while the placebo group not changed. While the study results are very gratifying, but the system in order to better determine its effectiveness and safety studies need larger sample.
■ Summary
Although people pathogenesis of male pattern baldness and female pattern hair loss for many years of research and investigation, but the exact pathogenesis is not entirely clear. Physician, the detailed understanding of the key factors in the development of the disease occurs is very important, which is conducive to the current understanding of the mechanism of drug treatment, but also conducive to more deeply understand the pathogenesis of this symptom, which eventually developed more treatments.
Drug treatment of male pattern baldness and female pattern hair loss has been a hot topic. Therefore, physicians should correctly understand and master a variety of drug treatment indications in a timely manner to provide information about hair Wholesale hair extension transplant hair friendly and non-drug treatment options to provide the best treatment for hair Friends, Friends of hair lifted as soon as the spiritual pain.