脱发的十大原因

原作者：
来源Top 10 Causes of Hair Loss
译者wwjun

Top 10 Causes of Hair Loss

脱发的十大原因

Those who have it love it. Those who don’t miss it. And those who are in the process of losing it, well, they’ll do anything to keep it. We’re talking of course about hair. While it’s easy to blame your parents for your thin hair or balding scalp, not all causes of hair loss trace back to genetics. You might be surprised to learn that there are dozens of reasons for it. And, while some are a little less common than others, it’s still important to understand how you lose your hair so that you’ll know how to prevent it.

拥有它的人喜欢它。没有它的人想念它。而那些正在失去它的人，则会想尽一切办法留住它。当然，我们说的就是头发。我们常常把头发稀少或者秃顶怪罪于我们的父母，但其实脱发的原因并不完全是遗传的。你也许会感到震惊，原来脱发的原因有这么多。虽然有些原因比较不常见，但是知道脱发的原因还是很重要的，这样我们才知道怎样防止掉发。

Here are the top 10 causes of hair loss.

以下是引起脱发的10大原因。

No.10 Tight Braids Or Pulled-Back Hair

第十.辫子扎得太紧或者向后梳头发

This cause is probably a bit more relevant to women, but even men should know that wearing hair in tight braids (like dreadlocks or cornrows) or having hair tightly pulled back (like in a ponytail) can lead to hair loss -- or what is medically known as traction alopecia. It is caused by chronic pulling of the hair, leading to gradual hair loss, mostly at the hairline. While it’s most commonly seen in African women, it’s also seen in men who wear hairpieces in the same location on the scalp for long periods of time.

这个原因可能跟女人的关系更大，但即使是男人，也应该知道把辫子扎得太紧（如非洲发绺或者玉米编发）或者向后梳发（如梳成马尾辫）会导致脱发——或者如医学上讲的牵引性脱发。这是由于长期的拉紧头发，会导致头发逐渐脱落，尤其是在发际线处。这种现象在非洲女性身上比较常见，也常见于那些长期把假发戴在同一区域的男人身上。

第九.拔毛发癖

No.9 Trichotillomania

Trichotillomania is the name given to the habitual plucking or pulling of the hair from the head or other parts of the body. While it’s still unclear whether trichotillomania should be classified as a habit or as an obsessive-compulsive disorder, the end result is the same. Over time, a bald spot will develop. If the habit stops, hair will typically regrow, but with excessive and long-term trichotillomania, scarring of the scalp can result, leading to permanent hair loss in the affected location!

拔毛发癖是指习惯性地从头上或者身体的其他部分拔扯毛发。虽然现在还不清楚拔毛发癖到底是应该归类于一种习惯还是认为是一种强迫性精神障碍，最后的结果却是一样的。久而久之，就会产生斑秃。如果改掉这个习惯，头发会重新长出，但是长期过度地拔毛发，给头皮造成伤害，在受影响区域会导致永久性的脱发。

No.8 Hypothyroidism

第八.甲状腺功能减退症

The thyroid is a small gland located in the front of the neck just below the voice box. It plays an important role in regulating the body’s metabolism through the release of various hormones. Hypothyroidism is an underproduction of certain hormones and is the most common cause of patchy hair loss known as alopecia areata (which can affect the whole body and not just the head). Hypothyroidism itself is caused by birth abnormalities, autoimmune diseases or surgery involving the removal of the thyroid.

甲状腺是位于颈部前端、喉头下方的一个小腺体。它通过释放多种激素来调节身体的新陈代谢，具有重要作用。甲状腺功能衰退症就是某种激素分泌较少，这是头发脱落形成斑秃的最常见原因（这可能影响整个身体而不仅仅是头部）。而甲状腺功能衰退症本身则是由出生异常，自身免疫疾病或者包括甲状腺切除手术在内的外科手术等引起的。

No.7 Autoimmune Disease

第七.自身免疫疾病

If you have diabetes or have arthritis, you've already been dealing with autoimmune diseases that arise when the body’s own immune system mistakenly attacks and destroys healthy body tissue. When the body’s immune system attacks hair follicles or other cells or tissues important to hair growth and maintenance, it can result in hair loss of various kinds, including cicatricial alopecia (a form of permanent hair loss) and telogen effluvium (which occurs when hair's growth cycle is disrupted).

如果你患有糖尿病或者关节炎，你自身的免疫系统会错误地攻击并破坏健康的机体组织时，这就引起了自身免疫疾病。当身体的免疫系统攻击毛囊或者其他对头发生长和维护很重要的细胞或组织时，就会造成各种形式的脱发，包括瘢痕性脱发（一种永久性脱发形式）和休止期脱发（当头发的生长周期中断时发生）。

No.6 Infection

第六.感染

Although a number of infections can lead to hair loss, the most common infection that affects the scalp and hair is ringworm. Don’t let the name fool you: Ringworm is actually caused by a fungus. Tinea capitis, as it’s more scientifically known, is caused by mold-like fungi called dermatophytes that thrive in warm, moist conditions and typically arise due to poor hygiene. While it affects mostly children, it can be caught at any age.

虽然很多感染都会导致脱发，但是影响头皮和头发最常见的感染是癣。不要让这个病名给骗了：癣实际上是由真菌引起的。科学上常说的头癣，是由一种称为皮肤真菌的霉菌样真菌引起的。这种真菌在温暖潮湿的环境下容易滋生，通常是因为不良的卫生习惯引发的。这种感染主要发生在各个年龄段的孩子身上。

No.5 Chemotherapy

第五.化疗

Cancer cells typically divide and grow faster than the body’s healthy cells. What allows chemotherapy to be so effective in stopping cancer is that it stops those cells that grow rapidly. Unfortunately, there are other cells in the body that grow rapidly as well -- like those in hair follicles. While there are cancer myths out there, experiencing near-total hair loss after chemotherapy isn't one of them. The loss could be gradual or dramatic, depending on the type of drug, but the end result is usually the same. Thankfully, the hair usually grows back!

癌细胞的分裂和成长速度通常比身体的健康细胞快。化疗之所以对治疗癌症有效是因为它让癌细胞停止快速增长。不幸的是，身体里还有一些细胞也生长得比较快，如毛囊处的细胞。既然癌症的谜底解开了，那么化疗后引起的头发将近全部脱落并不是治疗的目的。脱发的过程可能是逐渐的，也可能戏剧化的迅速脱落，这取决于药物的种类，但最终的结果基本是一样的。值得庆幸的是，通常头发还会再长出来。

No.4 Medication

第四.药物治疗

Most of the human population is well aware that chemotherapy drugs can lead to hair loss, but there are, in fact, dozens of other drugs that might cause hair to fall out. These include anti-thyroid medications, hormonal therapies (like birth control), anti-convulsants (for epilepsy),  anti-coagulants, beta-blockers, and many others. These medications tend to cause telogen effluvium, a rapid shedding of the hair that arises when a large number of hairs suddenly shift from a growth phase (known as anagen) to a resting phase (known as telogen), and then fall out when new hairs begin to grow.

绝大部分普通人都清楚地知道化疗药物会导致脱发，但实际上，许多其他药物也可能引起头发脱落。这其中包括抗甲状腺药物，激素药（如避孕药），抗惊厥药物（用于癫痫症），抗凝剂，β-阻断剂以及其它等等。这些药物往往会引起休止期脱发，大量头发在生长阶段（即生长期）突然迅速向休止期（即静止期）转变，这样在头发开始生长时就会脱落，于是就造成了头发迅速脱落。

No.3 Vitamin/Mineral Deficiency

第三.维生素/矿物质不足

Whether it’s because of a crash diet, general malnutrition or some genetic or biological defect, deficiencies in certain nutrients can cause hair loss. Probably the most common deficiency thought to contribute to hair loss is iron. Being severely low in iron can lead to iron-deficiency anemia, a condition that causes the body not to have enough red blood cells. Red blood cells are important because they carry oxygen to nearly every cell in the body, helping those cells maintain normal function. Deficiencies in other nutrients -- such as vitamin B (specifically B12) and protein  -- are thought to contribute to hair loss as well.

无论是由于快速节食，营养不均衡还是一些遗传的或生理缺陷引起的某些营养物不足，均会导致脱发。头发脱落通常是由于缺铁引起的。身体严重缺铁容易导致缺铁性贫血，就是身体没有足够的红细胞，红细胞对于人体而言非常重要，因为它的功能是给身体的每个细胞运送氧气，帮助这些细胞维持正常的功能。其他营养物不足——如维生素B（尤其是B12）和蛋白质——通常也会引起脱发。

No.2 Stress

第二.压力

Severe physical stress (like surgery) or severe psychological stress (like a death in the family) can have strange effects on the body. Severe stress typically sends the body into a state of shock, flooding it with various hormones and metabolites. This may lead to telogen effluvium, a shedding of the hair that we mentioned above. While the effects of acute stress on hair are well understood, what isn’t as clear is how chronic or long-term stress affects hair loss.

严重的身体压力（如手术）或者严重的心理压力（如家人亡故）对身体有着奇怪的影响。严重的压力常使身体处于休克状态，体内充斥着各种激素和代谢物。这可能会导致休止期脱发，即我们上面提到的迅速脱发。我们可以理解这种剧烈的压力对头发的影响，但是不太清楚那种慢性或者长期的压力是如何影响脱发的。

No.1 Male Pattern Baldness

第一.男性型脱发

Despite all the different causes of hair loss, the leading cause is one that we can’t do much about. Male pattern baldness, medically known as androgenetic alopecia, refers to hair thinning in an “M-shaped" pattern that is typically mentioned when men talk about balding. Over time, the hair follicles will change and shrink, leading to thinning hair. While many treatments are available, they aren’t guaranteed to work and most only slow progression (although some can lead to hair regrowth) and are not permanent solutions for hair loss. In the end, we’re all victims of our genes -- and that’s something that will never change.

尽管引起脱发的原因各不相同，但最主要的原因却是一个我们无法控制的因素。男性型脱发，医学上称为雄性遗传脱发，就是人们谈论秃顶时常提到的头发逐渐减少，呈“M型”状态。随着时间的推移，毛囊就会发生改变并收缩，导致头发稀疏。虽然现在有很多治疗方法，但并不是很有效，顶多是使得病情减缓（尽管有些能让头发再生），终究不是预防脱发的治疗方法。总而言之，我们都是基因的受害者——而且这是谁也无法改变的。

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