山西医大皮肤性病学课件-紫癜（Purpura）

PurpuraPurpuraismultifocalextravasationofbloodintotheskinormucousmembrane.Itismanifestedbydistinctivebrownishredorpurplishmaculesafewmillimetersindiameterresultingfromtheruptureofthecapillarywallsatthearteriolar-capillaryjunction.Petechiaearesuperficial,pinhead-sized(lessthan3mm),round,hemorrhagicmacules,brightredatfirst,thenbrownishorrustcolored.Theyaremostcommonlyseeninthedependentareas,areevanescent,occurincrops,regressoveraperiodofdays,andmostoftenimplyadisorderofplatelets,usuallythrombocytopenia.Theymayalsobeasignofabloodvesseldiseasesuchasscurvy.AnaphylactoidpurpuraHenoch-SchonleinPurpura(HSP)ischaracterizedbyintermittentpurpura,arthralgia(74%to84%),abdominalpain(61%to76%),andrenaldisease(44%to47%).Typically,palpablepurpuraappearsontheextensoraspectsoftheextremities,whichbecomehemorrhagicwithinadayandstarttofadeinabout5days.Newcorpsmayappearoveraperiodofafewweeks.Urticariallesions,vesicles,necorticpurpura,andhemangioma-likelesionsmayalsobepresentatsomestages.Itoccursprimarilyinmalechildren,withapeakagebetween4and8years;however,adultsmayalsobeaffected.Aviralinfectionorstreptococcalpharyngitisaretheusualtriggeringevent.Otherpossibilitiesincludeotherbacterialinfections,food,drug,chemicaltoxins,andlumphoma.Phenacetin,tetracycline,erythromycin,quinidine,andinsectbiteshaveallbeenincriminated.Inabout40%ofcasesthecutaneousmanifestationsareprecededbymildfever,headache,jointsymptoms,andabdominalpainforupto2weeks.Arthralgiaprogressingtoarthritisproducesperiarticularswellingaroundthekneesandankles.Abdominalpainandgastrointestinalbleedingmayoccuratanytimeduringthedisease;severeabdominalpainmayevensuggest-orportend-anacutesurgicalabdomen.Paralyticileusmayoccur.Vomiting,reboundtenderness,anddistensionareothermanifestations.Renalinvolvementmanifestsasmicroscopicorevengrosshematuriaandmayoccurin25%ormoreofpatients.Thelong-termprognosisinchildrenwithgrosshematuriaisverygood;however,progressivegolmerulardiseaseandrenalfailuremaydevelopinasmallpercentage,sothatcarefulfollow-upsupervisionisnecessaryforthosewithhematuria.TreatmentTreatmentissupportive.Theusualdurationofillnessis6to16weeks.Between5%and10%ofpatientswillhavepersistentorrecurrentdisease.Antispasmodics,antibiotics,andantiinflammatorydrugs,includ