Hypersensitivity reactions are exaggerated or inappropriate immunologic responses occurring in response to an antigen or allergen. Type I, II ...NCBISkiptomaincontentSkiptonavigationResourcesHowToAboutNCBIAccesskeysMyNCBISignintoNCBISignOutNCBIBookshelf.AserviceoftheNationalLibraryofMedicine,NationalInstitutesofHealth.StatPearls[Internet].TreasureIsland(FL):StatPearlsPublishing;2021Jan-.StatPearls[Internet].ShowdetailsTreasureIsland(FL):StatPearlsPublishing;2021Jan-.SearchtermImmediateHypersensitivityReactionsAngelA.JustizVaillant;RishikVashisht;PatrickM.Zito.AuthorInformationAuthorsAngelA.JustizVaillant1;RishikVashisht;PatrickM.Zito2.Affiliations1UniversityoftheWestIndies2UniversityofMiami;MillerSchoolofMedicineLastUpdate:June11,2021.ContinuingEducationActivityHypersensitivityreactionsareexaggeratedorinappropriateimmunologicresponsesoccurringinresponsetoanantigenorallergen.TypeI,IIandIIIhypersensitivityreactionsareknownasimmediatehypersensitivityreactionsbecausetheyoccurwithin24hoursofexposuretotheantigenorallergen.ImmediatehypersensitivityreactionsarepredominantlymediatedbyIgE,IgM,andIgGantibodies.Thisactivitydescribesthepathophysiologyoftheimmediatehypersensitivityreactions,reviewstheirevaluationandmanagement,andhighlightstheroleoftheinterprofessionalteaminthemanagementofaffectedpatients.Objectives:Describetheriskfactorsforimmediatehypersensitivityreactions.Reviewthehistoryandphysicalexamfindingsofimmediatehypersensitivityreactions.Outlinetreatmentoptionsforimmediatehypersensitivereactions.Summarizestrategiestoimprovecarecoordinationamongstinterprofessionalteammemberstoimproveoutcomesforpatientsaffectedbyimmediatehypersensitivereactions.Earncontinuingeducationcredits(CME/CE)onthistopic.IntroductionHypersensitivityreactions(HR)areimmuneresponsesthatareexaggeratedorinappropriateagainstanantigenorallergen.CoombsandGellclassifiedhypersensitivityreactions intofourforms.TypeI,typeII,andtypeIIIhypersensitivityreactionsareknownasimmediatehypersensitivityreactions(IHR)bec