脂溢性皮炎致病因素中马拉色菌致病作用的系统评价

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.     

马拉色菌属的研究进展

马拉色菌是一种寄生于人和动物正常皮肤表面的真菌,可导致机会感染而引起各种马拉色菌属相关疾病。马拉色菌的致病机制主要是分解脂质,导致角质形成细胞形态学改变和细胞凋亡。马拉色菌可引起花斑癣、脂溢性皮炎、马拉色菌毛囊炎等,在特应性皮炎中也起到变应原的作用。对于这些疾病的治疗可使用抗真菌药物。     

婴儿头面部脂溢性皮炎马拉色菌带菌情况分析

目的了解患头面部脂溢性皮炎的婴儿与正常婴儿头面部马拉色菌带菌情况及来源分析。方法采用胶带法粘取脂溢性皮炎患儿头面部皮损及其母亲胸前皮肤、正常婴儿额部皮肤及其母亲胸前皮肤等处鳞屑,接种于含菜籽油培养基进行真菌培养,分离马拉色菌,并用生理生化及形态学方法鉴定菌种。结果①4组150例标本中共分离出101株马拉色菌;②脂溢性皮炎患儿与正常婴儿马拉色菌培养阳性率以及菌种构成差异均无显著性意义;③脂溢性皮炎患儿与正常婴儿分别与其母亲的马拉色菌培养阳性率以及菌种构成比较差异均无显著性意义,菌种存在一致性,但一致性较差。结论马拉色菌是患儿皮肤的常驻菌;脂溢性皮炎患儿及正常婴儿皮肤马拉色菌可能部分来源于母亲。     

头皮屑和头皮脂溢性皮炎患者头皮脂类水平及马拉色菌数量的检测

目的:测定有头皮屑及头皮脂溢性皮炎患者与正常受试者头皮表面脂类水平及马拉色菌数量的差异。方法:使用sebumeter于洗发后连续4天测量受试者额、顶、枕部头皮皮脂,并于第4天真菌镜检马拉色菌,记录马拉色菌数量。结果:有头皮屑及头皮脂溢性皮炎组与正常对照组相比,马拉色菌数量显著增高,具有统计学意义(P<0.05)。头皮脂溢性皮炎组较头皮屑组的马拉色菌数量显著增高,具有统计学意义(P<0.05)。在头皮屑及头皮脂溢性皮炎组中,随着炎症程度加重,检出的马拉色菌孢子数增多。结论:马拉色菌感染可能与头皮屑多和脂溢性皮炎有关。     

脂溢性皮炎患者血清中抗马拉色菌抗体检测

为了探讨马拉色菌在脂溢性皮炎发病中的作用和意义,我们采用病例对照设计,以马拉色菌(原卵形糠秕孢子菌P.ovale)整菌(WPO)、胞外提取物(ECE)、胞壁提取物(CWE)、胞浆提取物(CPE)为抗原,用间接酶联免疫吸附试验(ELISA)方法检测37例脂溢性皮炎患者和正常人血清中的抗P.ovale抗体。脂溢性皮炎患者血清中抗WPO和抗CPEIgG抗体高于正常对照组(P<0.01),其平均OD值约为正常对照组的1.6～1.8倍,而抗ECE、CWEIgG抗体与正常对照组差异无显著性(P>0.05);4个抗原的IgASD均有不同程度上升,上升明显且具有统计学意义的是抗ECE、CPE的IgA(P<0.01,P<0.05);除抗WPOIgM升高外,余IgM抗体均有不同程度的下降。结果提示脂溢性皮炎的发病可能与马拉色菌相关,脂溢性皮炎患者可能存在某些分子水平上免疫调节方面的缺陷。     

糠秕马拉色菌相关皮肤病的免疫学研究现状

糠秕马拉色菌为人体皮肤正常菌群(亦为条件致病菌)之一,与之相关的皮肤疾病有:花斑癣、糠秕马拉色茁毛囊炎(原糠秕孢子菌毛囊炎)、脂溢性皮炎、特应性皮炎和银屑病等。对糠秕马拉色菌和与之相关的主要皮肤病的免疫学研究进行了综述,并对今后的研究设计和研究方法进行了展望。     

糠秕马拉色菌相关皮肤病的免疫学研究现状

糠秕马拉色菌为人体皮肤正常菌群（亦为条件致病菌）之一,与之相关的皮肤疾病有：花斑癣,糠秕马拉色菌毛囊炎（原糠秕孢子菌毛囊炎）脂溢性皮炎,特应性皮炎和银屑病等,对糠秕马拉色菌和与之有相关的主要皮肤病的免疫学研究进行了综述,并对今后的研究设计和研究方法进行了展望。     

马拉色菌致病相关因子研究进展

马拉色菌为人类正常皮肤寄居菌,但在一定条件下可导致疾病.其致病需要内外因素的综合作用,自身致病因素包括侵袭性酶、代谢产物、表皮细胞的相互作用、酵母相和菌丝相的形态转变、自身细胞壁脂质层特殊结构等.宿主易感因素包括机体微环境改变、雄激素、机体免疫力低下等多环节.综述马拉色菌致病性方面的研究进展.     

非特应性的湿疹皮炎患者皮肤马拉色菌携带情况

为探讨非特应性的湿疹皮炎患者皮肤马拉色菌携带情况，选取非特应性的温疹皮炎患者，参照Faergemann的方法取材，采用马拉色菌培养基培养。结果急性及慢性湿疹皮炎患者非脂溢部位皮损马拉色菌检出率显著高于正常人非脂溢部位，接触性皮炎及未分类湿疹患者非脂溢部位皮损马拉色菌检出率也显著高于正常人非脂溢部位。自身对照研究发现，慢性湿疹皮炎患者非脂溢部位皮损马拉色菌检出率显著高于自身正常非脂溢部位。结论示马拉色菌可能与一部分非特应性的湿疹皮炎有一定关系。     

马拉色菌与特应性皮炎

特应性皮炎的病因和发病机制目前尚未完全明确,近年研究发现马拉色菌可能诱发该病,综述马拉色菌在特应性皮炎患者的体表分布、针刺反应试验、血清IgE水平、斑贴试验、细胞和细胞因子水平以及抗马拉色菌感染的治疗等方面对马拉色菌与特应性皮炎及其相关性的研究,从而为诊断和治疗特应性皮炎提供理论基础。     

Skin diseases associated with Malassezia species

The yeasts of the genus Malassezia have been associated with a number of diseases affecting the human skin, such as pityriasis versicolor, Malassezia (Pityrosporum) folliculitis, seborrheic dermatitis and dandruff, atopic dermatitis, psoriasis, and--less commonly--with other dermatologic disorders such as confluent and reticulated papillomatosis, onychomycosis, and transient acantholytic dermatosis. Although Malassezia yeasts are a part of the normal microflora, under certain conditions they can cause superficial skin infection. The study of the clinical role of Malassezia species has been surrounded by controversy because of their fastidious nature in vitro, and relative difficulty in isolation, cultivation, and identification. Many studies have been published in the past few years after the taxonomic revision carried out in 1996 in which 7 species were recognized. Two new species have been recently described, one of which has been isolated from patients with atopic dermatitis. This review focuses on the clinical, mycologic, and immunologic aspects of the various skin diseases associated with Malassezia. It also highlights the importance of individual Malassezia species in the different dermatologic disorders related to these yeasts.     

Three etiologic facets of dandruff and seborrheic dermatitis: Malassezia fungi, sebaceous lipids, and individual sensitivity

Application of new molecular and biochemical tools has greatly increased our understanding of the organisms, mechanisms, and treatments of dandruff and seborrheic dermatitis. Dandruff results from at least three etiologic factors: Malassezia fungi, sebaceous secretions, and individual sensitivity. While Malassezia (formerly P. ovale) has long been a suspected cause, implicated by its presence on skin and lipophylic nature, lack of correlation between Malassezia number and the presence and severity of dandruff has remained perplexing. We have previously identified the Malassezia species correlating to dandruff and seborrheic dermatitis. In this report, we show that dandruff is mediated by Malassezia metabolites, specifically irritating free fatty acids released from sebaceous triglycerides. Investigation of the toxic Malassezia free fatty acid metabolites (represented by oleic acid) reveals the component of individual susceptibility. Malassezia metabolism results in increased levels of scalp free fatty acids. Of the three etiologic factors implicated in dandruff, Malassezia, sebaceous triglycerides, and individual susceptibility, Malassezia are the easiest to control. Pyrithione zinc kills Malassezia and all other fungi, and is highly effective against the Malassezia species actually found on scalp. Reduction in fungi reduces free fatty acids, thereby reducing scalp flaking and itch.     

Malassezia species in healthy skin and in dermatological conditions

The genus Malassezia comprises lipophilic species, the natural habitat of which is the skin of humans and other warm‐blooded animals. However, these species have been associated with a diversity of dermatological disorders and even systemic infections. Pityriasis versicolor is the only cutaneous disease etiologically connected to Malassezia yeasts. In the other dermatoses, such as Malassezia folliculitis, seborrheic dermatitis, atopic dermatitis, and psoriasis, these yeasts have been suggested to play pathogenic roles either as direct agents of infection or as trigger factors because there is no evidence that the organisms invade the skin. Malassezia yeasts have been classified into at least 14 species, of which eight have been isolated from human skin, including Malassezia furfur, Malassezia pachydermatis, Malassezia sympodialis, Malassezia slooffiae, Malassezia globosa, Malassezia obtusa, Malassezia restricta, Malassezia dermatis, Malassezia japonica, and Malassezia yamatoensis. Distributions of Malassezia species in the healthy body and in skin diseases have been investigated using culture‐based and molecular techniques, and variable results have been reported from different geographical regions. This article reviews and discusses the latest available data on the pathogenicity of Malassezia spp., their distributions in dermatological conditions and in healthy skin, discrepancies in the two methods of identification, and the susceptibility of Malassezia spp. to antifungals.     

Malassezia-Hefen und ihre Bedeutung in der Dermatologie

Yeasts of the genus Malassezia belong to the normal microflora of the human skin. In addition they are known to cause a variety of skin diseases; the most frequent of which is pityriasis versicolor. Malassezia yeasts are also thought to be associated with seborrheic dermatitis, dandruff and Malassezia folliculitis. Recently the significance of Malassezia yeasts as a trigger factor for atopic dermatitis of the head and neck region has been pointed out. The role of the Malassezia yeasts in these different diseases has been controversial in the past and remains an issue because of difficulties in isolation, culture and differentiation of the organism. Thanks to molecular techniques, 10 species can actually be differentiated. The article presents the different Malassezia-associated diseases, their clinical picture, diagnosis and appropriate therapy. In addition the speciation of Malassezia is reviewed.     

Malassezia yeasts and their significance in dermatology

Yeasts of the genus Malassezia belong to the normal microflora of the human skin. In addition they are known to cause a variety of skin diseases; the most frequent of which is pityriasis versicolor. Malassezia yeasts are also thought to be associated with seborrheic dermatitis, dandruff and Malassezia folliculitis. Recently the significance of Malassezia yeasts as a trigger factor for atopic dermatitis of the head and neck region has been pointed out. The role of the Malassezia yeasts in these different diseases has been controversial in the past and remains an issue because of difficulties in isolation, culture and differentiation of the organism. Thanks to molecular techniques, 10 species can actually be differentiated. The article presents the different Malassezia-associated diseases, their clinical picture, diagnosis and appropriate therapy. In addition the speciation of Malassezia is reviewed.     

花斑糠疹与马拉色菌毛囊炎相关危险因素和致病菌分析

目的 研究花斑糠疹和马拉色菌毛囊炎的相关危险因素和致病菌特点,并比较其差异。方法 收集我院临床花斑糠疹和马拉色菌毛囊炎患者,均以1：1设置病例对照组,调查发病相关因素,采用SPSS16.0软件进行单因素和多因素Logstic回归分析。培养阳性菌株采用形态学和生理生化学方法鉴定到菌种,比较菌种分布。结果 共收集到163例花斑糠疹和132马拉色菌毛囊炎患者。单因素回归分析显示与花斑糠疹发病相关的因素有多汗和油性皮肤,与马拉色菌毛囊炎发病相关的因素有男性、潮湿环境、多汗、油性皮肤、刺激性食物、甜腻食物。多因素回归分析显示花斑糠疹的危险因素有多汗和油性皮肤,马拉色菌毛囊炎的危险因素有多汗、油性皮肤、男性和甜腻性食物。两种疾病致病菌均以合轴马拉色菌为优势菌,但糠秕马拉色菌在毛囊炎中占较高比例。结论 多汗和油性皮肤是花斑糠疹和马拉色菌毛囊炎共同的危险因素,而男性、甜腻性食物为马拉色菌毛囊炎独有的危险因素,两种疾病致病分布也存在统计学差异。     

The role of Malassezia in atopic dermatitis affecting the head and neck of adults

Atopic dermatitis is a common chronic skin condition. A subset of patients with head and neck dermatitis may have a reaction to Malassezia flora fueling their disease. Although there are no documented differences in Malassezia species colonization, patients with head and neck atopic dermatitis are more likely to have positive skin prick test results and Malassezia-specific IgE compared with healthy control subjects and patients with atopy without head and neck dermatitis. There is no clear relationship with atopy patch testing. The reaction to Malassezia is likely related to both humoral- and cell-mediated immunity. Clinically, Malassezia allergy may be suspected in patients with atopic dermatitis and: (1) head and neck lesions; (2) exacerbations during adolescence or young adulthood; (3) severe lesions recalcitrant to conventional therapy; and (4) other atopic diseases. There is literature to suggest that these patients will benefit from a 1- to 2-month course of daily itraconazole or ketoconazole followed by long-term weekly treatment.     

基质金属蛋白酶与皮肤病的研究进展

基质金属蛋白酶是一类结构上高度同源的锌离子依赖内肽酶超家族，已经发现24个成员，依据作用底物不同，分属于6个亚组，主要由角质形成细胞、成纤维细胞、内皮细胞、中性粒细胞以及巨噬细胞等分泌。基质金属蛋白酶参与了多个信号通路，而与细胞分化、增殖、炎症密切相关，在细胞外基质降解、伤口愈合、组织重建方面发挥作用，参与多种皮肤病致病机制或创伤修复过程。深入了解基质金属蛋白酶在相关皮肤病的研究进展，有助于进一步探讨这些皮肤病的发病机制，甚至为治疗提供新的靶点。     

Seborrheic dermatitis

Seborrheic dermatitis is present in 1% to 3% of immunocompetent adults, and is more prevalent in men than in women. Seborrheic dermatitis may be seen in conjunction with other skin diseases, such as rosacea, blepharitis or ocular rosacea, and acne vulgaris. Malassezia yeasts have been associated with seborrheic dermatitis. Abnormal or inflammatory immune system reactions to these yeasts may be related to development of seborrheic dermatitis. Treatment modalities for seborrheic dermatitis include keratolytic agents, corticosteroids, and more recently, antifungal agents. Antifungal agents do not carry a risk of skin atrophy or telangiectasia with prolonged use, and it is more prudent to consider antifungals than corticosteroid preparations. The wide range of antifungal formulations available (creams, shampoos, or oral) provides safe, effective, and flexible treatment options for seborrheic dermatitis.     

Optimal Management of Fungal Infections of the Skin, Hair, and Nails

Superficial fungal infections are chronic and recurring conditions. Tinea capitis is a scalp infection, primarily affecting prepubescent children. Ringworm infections, such as tinea corporis and tinea cruris, involve the glabrous skin. Tinea nigra is a rare mycotic infection that may be related to travel abroad. Piedra, black or white, is limited to the hair shaft without involvement of the adjacent skin. Pityriasis (tinea) versicolor and seborrheic dermatitis are dermatoses associated with yeasts of the genus Malassezia that affect the lipid-rich areas of the body. The taxonomy of the Malassezia yeasts has been revised to include nine species, eight of which have been recovered from humans. Tinea pedis, an infection of the feet and toes, is one of the most common forms of dermatophytosis. Onychomycosis is a fungal infection affecting the nail bed and nail plate; it may be chronic and can be difficult to treat. In instances where the superficial fungal infection is severe or chronic, an oral antifungal agent should be considered. Terbinafine, itraconazole, and fluconazole are oral antifungals that are effective in the treatment of superficial mycoses.