皮肤性病学精品课件（中山大学）8-药疹.pptVIP

* * * * * * * * * * * * * * * * * * * * * * * * Binding of the antigen on cells by the corresponding antibody can cause activation of complements, opsonization of phagocytosis and ADCC to produce cell lysis and tissue injury. Type II hypersensitivity is also known as cytotoxic hypersensitivity and may affect a variety of organs and tissues. The antigens are normally endogenous, although exogenous chemicals (haptens) which can attach to cell membranes can also lead to type II hypersensitivity. Type II hypersensitivity is primarily mediated by antibodies of the IgM or IgG classes and complement. Phagocytes and NK cells may also play a role (ADCC). * * * * * * Extravasation of blood from disrupted blood vessels secondary to vasculitis * * * * * * * * * * * * * * * * * * * * * * SJS/TEN Causes: Most common: sulfamethoxazole(1-3/100,000), sulfadoxine with pyrimethamine (10/100,000), carbamazepine(14/100,000). Antibiotics (especially long-acting sulfa drugs and penicillins). Other: anticonvulsants, anti-inflammatory and allopurinol are also causes. Mechanism: unknown Presentation: spread rapidly (within 4 days) to their maximum extent Initial lesions: macular, iris lesions and bullae followed by desquamation, then slough. mucosal surfaces: difficult swallowing(GI), painful urination, photophobia, respiratory and alimentary tract involvement. Workup: Skin bx DDX: Paraneoplastic pemphigus (excluded with DIF). Graft-versus host disease (hx) and SSSS ( superficial blister). TENadvanced clinical and laboratory knowledge J AM ACAD DERMATOL 2013, 69:173e1-e13 J AM ACAD DERMATOL 2013, 69:187e1-e15 Etiology Majority: drug Minority: infection Mycoplasma P. CMV Dengue virus Immunopathogenesis Keratinocytes death mediated meanly by CD8 T cells CD8 T cell activation: ?? granzyme B, perforin and granulysin Antigen Pro-hapten HLA : HLA-B*1502: Aromatic antiepileptic agents==carbamazepine, phenytoin, oxcarbazapine, and lamotrigine Han-Chinese, Thai, Malaysianand South