Wheal and Flare reaction is which type of Hypersensitivity?
Correct Answer: Type I
Description: ANSWER: (A) Type IREF: APPENDIX-21 below for "HYPERSENSITIVITY REACTIONS"Wheal-and-flare reaction: (Stedman s Medical Dictionary)The 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:Allergy/Atopy/' AnaphylaxisTrue AnaphylaxisFree Ag - fixed IgE (on mast cell)Wheal and Flare reaction Casoni s test, anaphylaxis, prusnitz kunster reaction, Theobald smith phenomenon, Schultz dale phenomenon, Atopic dermatitis, Pseudoanaphylaxis (Anaphylactoid reaction)Free Ag - direct degranulation of mast cell (not IgE mediated)Iodine-containing radio contrast (me), aspirin and muscle reiaxants, morphineTYPE 2:AntibodydependentcytotoxichypersensitivityFree Ab - fixed AgIgM IgG/ComplementmediatedAutoimmune hemolytic anemiaHemolytic disease of the newborn (erythroblastosis fetalis)Autoimmune thrombocytopenic purpuraGoodpasture's 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 (SLE)Immunoglobulin therapyHyperacute graft rejectionAcute necrotizing vasculitisPolyarteritis nodosa Post streptococcal glomerulonephritisShick s testTYPE 4: Delayedhypersensitivity,cell-mediated,antibody-independentAg -T cell mediated (CD4/CD8)Delayed: CD4mediated .contact & tuberculin types with in 72 hours, Granulomatous type; 21-28 days]Contact dermatitis; Mantoux (tuberculin) testLepromin testChronic transplant rejectionMultiple sclerosisPhlyctenular keratoconjunctivitisJones mote reaction (cutaneous basophilic hypersensitivity)Direct 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 falsely)HyperacuteType 3AcuteType 4 >2 (both if provided)Acute cellular rejection = type 4 (better prognosis) Acute vascular rejection = type 2ChronicType 2
Category:
Microbiology
Get More
Subject Mock Tests
Practice with over 200,000 questions from various medical subjects and improve your knowledge.
Attempt a mock test nowMock Exam
Take an exam with 100 random questions selected from all subjects to test your knowledge.
Coming SoonGet More
Subject Mock Tests
Try practicing mock tests with over 200,000 questions from various medical subjects.
Attempt a mock test now