<prompt> Wheal and Flare reaction is which type of Hypersensitivity?Type IType IIType IIIType IV  <response>: ANSWER: A Type IREF: APPENDIX-21 below for HYPERSENSITIVITY REACTIONSWheal-and-flare reaction: Stedman s Medical DictionaryThe characteristic immediate reaction to an injected allergen in a skin test, in which an irregular blanched wheal, appears surrounded by an area of redness. Also called as wheal and erythema reaction. APPENDIX - 21Hypersessitivity ReactionsTYPE 1:AllergyAtopy AnaphylaxisTrue AnaphylaxisFree Ag - fixed IgE on mast cellWheal and Flare reaction Casoni s test, anaphylaxis, prusnitz kunster reaction, Theobald smith phenomenon, Schultz dale phenomenon, Atopic dermatitis, Pseudoanaphylaxis Anaphylactoid reactionFree Ag - direct degranulation of mast cell not IgE mediatedIodine-containing radio contrast me, aspirin and muscle reiaxants, morphineTYPE 2:AntibodydependentcytotoxichypersensitivityFree Ab - fixed AgIgM IgGComplementmediatedAutoimmune hemolytic anemiaHemolytic disease of the newborn erythroblastosis fetalisAutoimmune thrombocytopenic purpuraGoodpastures syndrome: Pemphigus vulgarisBullous pemphigoid; Acute rheumatic feverPernicious anemia: Myasthenia gravis; Graves diseaseADCC- antibody- dependent cell-mediated cytotoxicityAcute chronic transplant rejectionTYPE 3: Immune complexFree Ag Free Ab - Immune complexSerum sicknessArthus reactionSystemic lupus erythematosus SLEImmunoglobulin therapyHyperacute graft rejectionAcute necrotizing vasculitisPolyarteritis nodosa Post streptococcal glomerulonephritisShick s testTYPE 4: Delayedhypersensitivity,cell-mediated,antibody-independentAg -T cell mediated CD4CD8Delayed: CD4mediated .contact tuberculin types with in 72 hours, Granulomatous type; 21-28 daysContact dermatitis; Mantoux tuberculin testLepromin testChronic transplant rejectionMultiple sclerosisPhlyctenular keratoconjunctivitisJones mote reaction cutaneous basophilic hypersensitivityDirect cell toxicity:CD8 mediatedPerforin dependent killingFas-FasL dependent killingAlso know: Graft rejection is type 4 hypersensitivity unless type is provided. Most of the MCQ guides have quoted this falselyHyperacuteType 3AcuteType 4 2 both if providedAcute cellular rejection type 4 better prognosis Acute vascular rejection type 2ChronicType 2 