为什么男性型脱发(AGA)会导致 M 型发际线。

この記事の概要

雄激素性脱发(AGA)中的 M 型发际线主要是由荷尔蒙和遗传因素造成的。 以下内容解释了出现 M 型头发稀疏的原因。

1. DHT(双氢睾酮)的影响

AGA 主要是由DHT(双氢睾酮)引起的,这是一种影响毛囊的雄性激素。

  • DHT 作用:DHT 对头皮的某些部位,尤其是前额(发际线)和顶发的毛囊产生强烈的作用,导致毛囊萎缩。因此,头发的生长周期缩短,头发变得稀疏、短小和脱落。
  • 形成 M 型的原因:DHT 对前额太阳穴部位的影响尤其强烈。由于该区域的毛囊对 DHT 比较敏感,发际线两端(太阳穴区域)的头发会首先后退,从而使中央部分的头发保留下来,形成M 型

2. 遗传因素

由于遗传因素,AGA 被认为更容易受到 DHT 的影响。特别是,遗传往往决定了一个人的毛囊是否更容易受到 DHT 的影响。

  • 遗传影响:如果家族中有头发稀疏的人,就更有可能患上 AGA。如果父亲或祖父患有 AGA,某些基因就会受到影响,他们的后代对 DHT 同样敏感,脱发往往从太阳穴部位开始。
  • 个体差异:由于遗传因素,太阳穴和顶叶区域对 DHT 的敏感程度存在个体差异,从而导致 M 型进展模式不同。

3. 头皮易受 DHT 影响

有些部位比其他部位更容易受到 DHT 的影响。

  • 额头和太阳穴部位:该部位的毛囊对 DHT 非常敏感。因此,前额的头发开始从太阳穴部位后退,形成 M 型稀疏头发。
  • 后脑勺和两侧:另一方面,后脑勺和头两侧的毛囊受 DHT 的影响较小,这些部位的头发通常不容易变稀疏。因此,即使 AGA 继续发展,这些部位的头发也会保持相对密度。

4. 进展模式

M 型头发稀疏是一种典型的 AGA 进展模式,根据进展程度的不同,M 的程度也不同。

  • 早期:太阳穴部位的头发逐渐后退,前额的发际线逐渐开始像字母 M。在这一阶段,头发稀疏的程度有限。
  • 渐进期:太阳穴区域进一步后退,M 型变得更加明显。在这一阶段,发际线中心仍相对完整,但头发开始整体变稀疏。
  • 严重阶段:在更晚的阶段,M 型变得更加明显,最终整个发际线都会后退,头顶的头发也会变得稀疏。

5. M 型脱发的治疗和对策

与其他 AGA 一样,M 型头发稀疏也可以通过适当的治疗得到减缓或改善。

  • 非那雄胺(Finasteride)和度他雄胺(Dutasteride):这类口服药物可抑制 DHT 的产生,支持头发生长;可减缓 M 型头型的发展;还能有效降低脱发风险,防止脱发;还能有效防止脱发。
  • 米诺地尔:米诺地尔通过刺激血液流动和激活毛囊来促进头发生长。它可用于局部或口服治疗,对 M 型脱发有效。
  • 毛发移植:如果 M 型头发过于稀疏,可以选择毛发移植手术。从后脑或侧脑移植抗 DHT 的头发可改善 M 型稀疏头发。

摘要

M 型头发稀疏的主要原因是DHT(双氢睾酮)对前额和太阳穴部位的毛囊产生强烈影响,从而导致这些部位开始脱发。遗传因素和荷尔蒙影响密切相关,随着病情的发展,M 型脱发会变得更加明显。适当的治疗可以减少病情发展,改善脱发状况。

この記事の監修者

岡 博史 医師(医学博士) ヒロクリニック統括院長

慶應義塾大学医学部卒業。慶應義塾大学皮膚科学教室助手を経て、2008年ヒロ皮フ形成クリニックを開業。日本皮膚科学会認定皮膚科専門医・日本医師会認定産業医。

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Why male pattern baldness (AGA) causes an M-shaped hairline

この記事の概要

The M-shaped hairline in androgenetic alopecia (AGA) is mainly due to hormonal and genetic factors. Below are the reasons why M-shaped thinning hair occurs.

1. Influence of DHT (dihydrotestosterone)

AGA is mainly caused by DHT (dihydrotestosterone ), a type of male hormone that affects hair follicles. DHT is a hormone formed when testosterone is converted by 5-alpha reductase enzyme, which adversely affects hair follicles.

  • DHT Action: DHT acts strongly on certain areas of the scalp, especially the frontal (hairline) and parietal hair follicles, causing them to atrophy. As a result, the hair cycle is shortened and hair becomes thin and short and falls out.
  • Reason for the M-shape: The effects of DHT are particularly strong in the temple area of the forehead.Because the hair follicles in this area are sensitive to DHT, hair recedes first from both ends of the hairline (temple area), resulting in the center portion remaining, forming an M-shaped pattern.

2. Genetic factors

AGA is considered to be susceptible to DHT due to genetic factors. In particular, genetics often determines whether a person has hair follicles that are highly susceptible to DHT.

  • Genetic Influence: AGA is more likely to occur if there is someone in the family with thinning hair. If a father or grandfather had AGA, certain genes are affected and their offspring are similarly sensitive to DHT, and hair loss often begins in the temple area.
  • Individual differences: Due to genetic factors, there are individual differences in the degree to which the temple and parietal areas are susceptible to DHT, resulting in different patterns of M-shaped progression.

DHT sensitivity of the scalp

Some areas are more susceptible to DHT than others.

  • Frontal and temple areas: Hair follicles in these areas are very sensitive to DHT. Therefore, the forehead hair begins to recede from the temples, forming M-shaped thinning hair.
  • Occipital and temporal areas: On the other hand, hair follicles in the occipital and temporal areas are less susceptible to DHT, and hair in these areas is usually less prone to thinning. Therefore, even when AGA progresses, these areas tend to remain and hair density is relatively maintained.

4. pattern of progression

M-shaped thinning hair is one of the typical AGA progression patterns, and the degree of M-shaped thinning varies according to the degree of progression.

  • Early stage: The hair at the temples gradually recedes, and the hairline of the forehead gradually begins to look like the letter M. In this stage, the extent of thinning hair is limited. At this stage, the extent of thinning hair is limited.
  • Progressive stage: The temple area recedes further, and the M-shape becomes more pronounced. At this stage, the center of the hairline is still relatively intact, but the hair begins to thin overall.
  • Severe stage: In more advanced stages, the M-shape becomes more pronounced and eventually the entire hairline recedes, with thinning hair toward the crown of the head.

5. treatment and countermeasures for M-shaped hair loss

Like other AGAs, M-shaped thinning hair can be slowed or improved with appropriate treatment.

  • Finasteride or Dutasteride: These oral medications inhibit DHT production and support hair growth; they can slow the progression of the M-shape; they can be used to treat hair loss; they can be used to treat hair loss; they can be used to treat hair loss; and they can be used to treat hair loss.
  • Minoxidil: Minoxidil promotes hair growth by stimulating blood flow and activating hair follicles. Used as a topical or oral medication, it is also effective for M-shaped hair loss.
  • Hair transplantation: If the M-shape has progressed too far, hair transplant surgery is an option. By transplanting DHT-resistant hair from the back or side of the head, M-shaped thinning hair can be improved.

Summary

The main cause of M-shaped thinning hair is that DHT (dihydrotestosterone) has a strong effect on the hair follicles in the frontal and temple areas, and hair loss begins in those areas. Genetic factors and hormonal influences are strongly involved, and as the disease progresses, the M-shaped form becomes more pronounced. Appropriate treatment can reduce the progression and improve hair loss.

この記事の監修者

岡 博史 医師(医学博士) ヒロクリニック統括院長

慶應義塾大学医学部卒業。慶應義塾大学皮膚科学教室助手を経て、2008年ヒロ皮フ形成クリニックを開業。日本皮膚科学会認定皮膚科専門医・日本医師会認定産業医。

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本メディアの記事は編集ポリシー(コンテンツ制作方針)に基づいて制作・監修されています。