Is androgenetic alopecia a photoaggravated dermatosis?
Is androgenetic alopecia a photoaggravated dermatosis?
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DOI：
10.1159/000074111
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发表时间：
2003-01-01
期刊：
影响因子：
3.4
通讯作者：
Trüeb, RM
中科院分区：
文献类型：
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作者：
Trüeb, RM
雄激素性脱发（阿加）中头皮毛发的逐渐变薄导致头皮对紫外线辐射（UVR）的自然保护逐渐下降。头皮的许多病理状况显然与UVR有关，特别是慢性光损伤的秃头头皮的光敏性疾病和病症。紫外线辐射最重要的慢性效应是光致癌和日光性弹性组织变性。除此之外，糜烂性脓疱性皮肤病和“红头皮”是秃头头皮特有的独特疾病。虽然持续的紫外线照射对未受保护的头皮的影响是很好的理解，但紫外线照射对脱发的影响却被广泛忽视。然而，临床观察和理论考虑表明，紫外线辐射可能有负面影响：急性休止期脱发从紫外线辐射已被描述，并产生卟啉的丙酸杆菌属。在毛囊皮脂腺管，与卟啉的光活化导致氧化组织损伤，已被牵连在毛囊微炎症。另外，角质形成细胞本身可能会对紫外线辐射的物理化学应激产生反应，除了刺激物和污染物外，还会产生自由基氧和一氧化氮，并释放促炎细胞因子，最终导致毛囊浅表部分毛囊干细胞的假定部位受损。由于所有这些涉及脱发的过程都有一个共同的特征，即它们是由暴露于阳光下引起或加剧的，因此提出阿加是一种需要光防护的光加重皮肤病。版权所有（C）2003 S. Karger AG，巴塞尔。
Progressive thinning of the scalp hair in androgenetic alopecia (AGA) results in a gradual decline in natural protection of the scalp from ultraviolet radiation (UVR). A number of pathologic conditions of the scalp are evidently related to UVR, particularly photosensitive diseases and disorders of the chronically photodamaged bald scalp. The most important chronic effects of UVR are photocarcinogenesis and solar elastosis. Besides these, erosive pustular dermatosis and 'red scalp' are distinct disorders peculiar to the balding scalp. While the consequences of sustained UVR on the unprotected scalp are well appreciated, the effects of UVR on hair loss have widely been ignored. However, clinical observations and theoretical considerations suggest that UVR may have negative effects: acute telogen effluvium from UVR has been described, and the production of porphyrins by Propionibacterium sp. in the pilosebaceous duct, with photoactivation of porphyrins leading to oxidative tissue injury, has been implicated in follicular microinflammation. Alternatively, keratinocytes themselves may respond physicochemical stress from UVR, besides irritants and pollutants, by producing radical oxygen species and nitric oxide and by releasing proinflammatory cytokines, eventually leading to injury of the putative site of follicular stem cells in the superficial portion of the hair follicle. Since all of these processes involved in hair loss share the common feature that they are induced or exacerbated by exposure to sunlight, it is proposed that AGA is a photoaggravated dermatosis that requires photoprotection. Copyright (C) 2003 S. Karger AG, Basel.