This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunity, Subject name: Pathology
[{'content': 'Steven Johnson Syndrome is seen with what kind of hypersensitivity reaction? \nSelect and explain. \nA. Type 1, B. Type 2, C. Type 3, D. Type 4', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ref: Chapter 55, Harrison, 19th edition Clinical Features of Severe Cutaneous Drug ReactionsDiagnosisMucosal lesionsTypical skin lesionsStevens- Johnson syndromeErosions usually at two or more sitesSmall blisters on dusky purpuric macules or atypical targets; rare areas of confluence; detachment <=10% of body surface area DiagnosisMucosal LesionsTypical skin lesionsToxic epidermal necrolysisErosions usually at two or more sitesIndividual lesions like those seen in Stevens- Johnson syndrome; confluent erythema; outer layer of epidermis separates readily from basal layer with lateral pressure; large sheet of necrotic epidermis; total detachment of >30% of body surface areaClassification of Adverse Drug Reactions Based on Immune PathwayHypersensitivitytypeKey pathwayAdverse drug reaction typeType IIgEUrticaria, angioedema, anaphylaxisType IIIgG-mediated cyto-toxicityDrug induced hemolysisType IIIImmune complexVasculitis, serum sickness, drug-induced lupusType IV bT lymphocyte- mediated eosinophil inflammationTuberculin skin test, contact dermatitisType IV cT lymphocyte- mediated cytotoxic lymphocyte inflammationDrug-induced hypersensitivity syndromeMorbiliform eruptionType IV dT lymphocyte- mediated neutrophil inflammationAcute generalized exanthematouspustulosis', 'role': 'assistant'}]