Alopecia - alopecia

Japanese: 脱毛症 - だつもうしょう

Hair has a lifespan, and physiologically we lose 70 to 80 hairs per day; however, when an abnormally large amount falls out and the hair becomes sparse, or when a large number of hairs fall out in certain areas, resulting in baldness, it is called alopecia, also known as baldness, baldness, or simply "baldness."

[Kimiko Saito]

Congenital alopecia

At birth, the baby has normal vellus hair, which often falls out and does not grow back within 2-3 months of birth. It is an abnormal development of hair follicles, and in some cases the only affected area is hair, while in other cases the baby does not sweat due to the absence of sweat glands, and there may also be cases where the baby has missing nails or teeth. There is no treatment, so the baby is forced to wear a prosthetic hairpiece (wig) at an early stage.

[Kimiko Saito]

Alopecia areata

This disease mainly affects the scalp, causing sudden, circular, sharply demarcated bald areas. As there are no symptoms, it is often discovered at a beauty salon or barber shop. Usually, the bald area is 2-3 cm in diameter and is located in one place, but sometimes multiple areas merge into an irregular shape, or the entire head of hair falls out. It is also called the Taiwanese shaved head. The skin of the bald area usually shows no abnormalities, but it may be slightly sunken, puffy, or reddish compared to the surrounding area. When the lesion is examined under a microscope, inflammation is seen around the hair follicles. Usually, scalp hair is affected, but eyebrows, eyelashes, and beard may fall out, and all body hair may fall out. Nails may also have small dents or a rough surface. Hair around the expanding lesion can be pulled gently and painlessly, and the hair roots may become thinner at the tips. The course of the condition varies, and in most cases hair growth returns to normal within 2-3 months, but in some cases hair growth does not continue for years or recurs repeatedly, and this condition is also called malignant alopecia. When hair regrows, thin, soft hair grows and gradually returns to normal, but sometimes chilblains may appear temporarily. There are various theories about the cause, including allergy, focal infection, hair growth cycle disorder, psychosomatic causes, endocrine disorders, autoimmunity, and a multicause theory that these causes are intertwined, but there is no conclusive answer. Treatment is based on these theories or is empirical, and includes systemic therapy with glycyrrhizin, pantothenic acid, and tranquilizers, topical application of adrenal cortical hormones and local blood flow improvers, exposure to sunlamps, and local cryotherapy.

[Kimiko Saito]

Male pattern baldness

This is what is commonly known as premature baldness, also known as juvenile alopecia or male pattern baldness. From around the age of 20 to 30, the condition begins to show a characteristic pattern of baldness, with a receding hairline on the forehead and thinning on the top of the head. It is caused by genetic predisposition and the male hormone androgen. In women, unless they have an endocrine disorder, this type of hair loss does not occur until they are older. There is no good treatment.

[Kimiko Saito]

Senile alopecia

It belongs to male pattern baldness and the baldness follows exactly the same pattern, but it usually begins after the age of 40 to 50. There is no good treatment.

[Kimiko Saito]

Pityriasis alopecia

This is a condition where hair thins as dandruff continues, and is often seen in the early stages of male pattern baldness. Treat dandruff.

[Kimiko Saito]

Trichotillomania

Hair loss caused by a person plucking out their own hair is also known as trichotillomania. Sometimes broken hairs remain in the bald patch, and bloody spots may be found. It is most common on scalp hair that is easily reachable, but can also be seen on other types of hair. There is often an underlying psychological factor, such as neurosis, depression, or hysteria, and in children it is accompanied by frustration and emotional restlessness. Repeated plucking causes the hair roots to atrophy and become irreversible.

[Kimiko Saito]

Symptomatic alopecia

This includes hair loss caused by febrile infectious diseases such as typhoid fever and pneumonia, chronic infectious diseases such as tuberculosis, leprosy, and syphilis, systemic diseases such as lupus erythematosus, dermatomyositis, scleroderma, diabetes, and endocrine disorders, radiation exposure, localized trauma, burns, fungal and bacterial infections, tumors, and drugs such as antitumor drugs. When hair in a certain area is constantly pulled, such as in a traditional Japanese hairstyle or ponytail, or compressed for a long time by a pillow or hat, hair loss occurs in that area (mechanical hair loss). It is necessary to remove the cause, such as treating the underlying disease.

[Kimiko Saito]

"Alopecia and Baldness" by Oya Zensetsu (Sogen Medical Paperback)" ▽ "The Hair Doctor" by I. I. Roubaud, translated by Fujiwara Goro (1962, Hakuyosha)

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

Japanese:

毛髪には寿命があって、生理的には1日70～80本の抜け毛があるが、異常に多く抜けて毛がまばらになったり、部分的に多数の毛が脱落して「はげ」た場合を脱毛症といい、禿髪(とくはつ)症、禿頭病あるいは俗に「はげ」ともよばれる。

［齋藤公子］

先天性脱毛症

生まれたときには軟毛が普通に生えていて生後2～3か月の間に抜けたまま生えてこない場合が多い。毛嚢(もうのう)（毛包）の発生異常で、障害が毛髪のみのものと、汗腺(かんせん)がないために汗をかかなかったり、爪(つめ)や歯の欠損を伴う場合もある。治療法はなく早期に義髪（かつら）を装用する。

［齋藤公子］

円形脱毛症

おもに頭部に突然円形の境界明瞭(めいりょう)な脱毛部を生ずる病気である。自覚症状がないため、多くは美容院や理髪店で発見される。通常直径2～3センチメートルの脱毛部が1か所にみられるが、ときには多発して不規則な形に融合したり、頭髪が全部脱落してしまうこともある。台湾坊主ともよばれる。はげた部分の皮膚は普通ほとんど異常を認めないが、周囲より多少へこんでいたり、ぶよぶよした感じがしたり、赤みを帯びたりすることもある。病巣部を顕微鏡で調べると毛嚢の周囲に炎症がみられる。通常、頭髪が侵されるが、まゆげ、まつげ、ひげなどが抜けたり全身の毛が全部脱落する場合もあり、爪にも点状のへこみを生じたり表面がざらざらになったりする。拡大しつつある病巣周囲の毛髪は、軽く引っ張ると痛みを伴わずに容易に抜け、毛根をみると先のほうが細くなっている。経過はいろいろで、2～3か月で常態に復することが多いが、年余にわたり発毛しなかったり、再発を繰り返す場合があり、悪性脱毛症ともよばれる。毛が再生してくる場合、細く柔らかい毛が生えてしだいに正常化するが、ときには一過性にしらがを生ずる場合もある。原因については、アレルギー説、病巣感染説、毛成長周期障害説、精神身体医学的原因説、内分泌障害説、自己免疫説、あるいはこれらの諸原因が絡み合って生ずるとする多原因説など諸説があるが、決定的なものはない。治療法は、これらの原因説に従い、あるいは経験的にグリチルリチン、パントテン酸、精神安定薬などの全身療法と、副腎(ふくじん)皮質ホルモン剤、局所血流改善剤の外用、太陽灯照射、局所凍結療法などが行われる。

［齋藤公子］

壮年性脱毛症

俗にいう若はげのことで、若年性脱毛症、男性型脱毛症ともいう。20～30歳ころから額の生え際が後退したり頭頂部が薄くなるなど、特徴的なはげ方をする。遺伝的な素因と男性ホルモンのアンドロゲンが関与する。女性では内分泌障害がない限り、高齢にならないとこの形の脱毛はおこらない。よい治療法はない。

［齋藤公子］

老人性脱毛症

男性型脱毛症に属し、はげ方はまったく同じ形をとるが、発症年齢が40～50歳以後である。よい治療法はない。

［齋藤公子］

粃糠性脱毛症

ふけ症が続くうちに毛が薄くなるもので、壮年性脱毛症の初期にしばしばみられる。ふけ症の手当てをする。

［齋藤公子］

抜毛症

自分で毛を抜き取るために生ずる脱毛で、抜毛狂、トリコチロマニアともいう。脱毛巣内に途中で切れた毛が残っていたり、点状の血痂(けっか)が付着していることがある。手の届きやすい頭髪に多いが、そのほかの毛にもみられる。神経症やうつ病、ヒステリーなどの精神的要素が根底にあることが多く、小児では欲求不満や情動不安を伴う。抜去が繰り返されると毛根が萎縮(いしゅく)して元に戻らなくなる。

［齋藤公子］

症候性脱毛症

腸チフスや肺炎などの熱性伝染病、結核、らい、梅毒などの慢性感染症、エリテマトーデス、皮膚筋炎、強皮症、糖尿病、内分泌疾患などの全身病、放射線照射、局所の外傷、熱傷、真菌や細菌感染症、腫瘍(しゅよう)などのほか、抗腫瘍薬などの薬物による脱毛も含まれる。日本髪やポニーテールなど一定部位の毛髪が絶えず引っ張られたり、枕(まくら)や帽子などで長時間圧迫されると、その部分に脱毛がおこる（機械的脱毛）。原因となる病気の治療など、原因を除去することが必要である。

［齋藤公子］

『大矢全節著『無毛症と禿頭』（創元医学新書）』▽『I・I・ルーボー著、藤原五郎訳『毛髪ドクター』（1962・白揚社）』

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