临床医学荨麻疹课件

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1、荨麻疹Urticaria定义俗称风疹块,为皮肤和粘膜因血管扩张。血浆外渗而引起的一种暂时性红斑和水肿反应,由真皮乳头层血管扩张，血浆渗出所致。临床上较为常见。Urticariaorhivesasitiscommonlycalled,isanitchyrashconsistingoflocalizedswellingsoftheskinthatusuallylastforafewhoursbeforefadingaway.Whenurticariadevelopsaroundloosetissuesoftheeyesorl

2、ips,theaffectedareamayswellexcessively.FeturesEachindividualhivelastsafewhoursbeforefadingaway,leavingnotrace.[病因与发病机理]荨麻疹病因十分复杂，而且大多数患者原因难觅，特别是慢性型病人。引起本病发病的最常见原因有：食物：从主食到副食的许多食物，甚至包括食品添加剂、饮料等可能成为荨麻疹的因。其中以蛋白质、如鱼类、虾、甲壳类、蛋类、牛奶、肉等尤为常见。[病因与发病机理]药物：药物荨麻疹在临床上颇为常见，以青霉

3、素、痢特灵、阿斯匹林等引起者居多；使用磺胺制剂、链霉素、四环素或氯霉素后有时也可发生本病。此外，象可待因、吗咖、维生素B1等引发荨麻疹也屡见报告。[病因与发病机理]感染：细菌、病毒、原虫、蠕虫、真菌等病原微生物感染与荨麻疹发病，对某些患者至关重要，甚至连虫咬或蜂螫刺都可导致荨麻疹发生。花粉及其它吸入物：如各种花粉、屋尘、动物皮屑等吸入物招引本病亦不乏其例。此外，精神因素、物理因素、全身性疾病、遗传素质等也可成为荨麻诊发病的原因。发病机制PathogenesisImmune-mediatedurticariacan

4、becausedby3of4typesofimmunemechanisms.ThetypeIallergicIgEresponseisinitiatedbyantigen-mediatedIgEimmunecomplexesthatbindandcross-linkFcreceptorsonthesurfaceofmastcellsandbasophils.ThetypesofantigensthatbindtoIgEarevariedandincludeproteins,polysaccharides,andother

5、immunogenicmolecules.TypeIIresponsesaremediatedbycytotoxicTcells.Thediseaseprocessactivatesbyproductsthatcauseurticarialvasculitisorbullouspemphigoid.TypeIIIimmune-complexdiseaseisassociatedwithsystemiclupuserythematosusandotherconnectivetissuedisordersthatactiva

6、teurticaria.Early-phasereactionLate-phasereactionImmune-mediatedurticariaNon–immune-mediatedChemicalsthatcandirectlyinducemastcelldegranulation,presumablybyalteringthemembraneproperties,causenon–immune-mediatedurticaria.Commonagentsassociatedwithdirectmastcellact

7、ivationareopiates,antibiotics,curare,radiocontrastmedia,azodyes,aspirin,andaspirinderivatives.ClinicalFeatures&ClasifacationAcuteurticariaChronicurticariaSpecifictypesofurticariaWhatdoestherashofacuteurticarialooklike?Therashusuallyappearssuddenlyandcanaffectanya

8、reaofskin.Smallraisedareascalledwhealsdevelopontheskin.Thewhealslooklikemildblistersandtheyareitchy.Eachwhealiswhiteorredandisusuallysurroundedbyasmallredareao