脂溢性皮炎致病因素中马拉色菌致病作用的系统评价

The etiology of seborrheic dermatitis:a systematic review

目的:明确脂溢性皮炎的致病因素以及马拉色菌在致病中是否起重要作用。方法:应用计算机和人工检索国内外与脂溢性皮炎研究有关的文献,按照循证医学非随机研究的系统评价方法,分析脂溢性皮炎病因学研究的证据,并进行综合评价。结果:自1950年以来有关病因学研究的49篇外文文献均认为其发病是多因素综合作用,基本集中在马拉色菌属酵母、脂质作用和个体易感性3个方面,其中以对马拉色菌致病性研究最多。5篇中文病因学研究文献中4篇不符合质量要求。结论:脂溢性皮炎的发病主要是在个体易感性基础上,机体对共生的马拉色菌菌体,及其脂酶分解皮脂产生游离脂肪酸的反应性增强,破坏皮肤屏障功能并引起皮肤炎症反应。抗真菌治疗可通过减少马拉色菌菌量而缓解皮肤炎症,提示马拉色菌在脂溢性皮炎的发病机制中起重要作用。

Objective： To investigate the etiology of seborrheic dermatitis and the pathogenic role of Malassezia species. Methods： We searched, by computer and manually, the foreign and domestic literature related to the etiology of seborrheic dermatitis published since 1950s, and according to the methods of non-randomized studies of evidence-based medicine, sys- tematically evaluated the evidence about its etiology. Results： Fifty articles supported the theory that there exist multiple factors and mostly focused on the role of the Malassezia （previously Pityrosporum） yeasts, lipid and individual susceptivity, espe- cially the pathogenicity of Malassezia species. Four articles in Chinese were eliminated due to their deficiency of design and method of experiment. Conclusions： Our results suggested that seborrheic dermatitis, based on the individual susceptivity, is caused by Malassezia yeasts and its secreted lipase which can digest sebum and release free fatty acids. All of above may lead to breakdown of skin barrier and then inflammatory reaction was occurred. Antifungal therapy reduces the number of Malassezia yeasts on the skin and lead to an improvement in seborrheic dermatitis, which also suggest Malassezia yeasts play an importment role in the etiology of it.