<prompt> 60 year female with tense bulla in lower extremity and subepidermal bullous lesion on microscopy, diagnosis is-Bullous pemphigoidPemphigus vulgarisErythema multiformeDermatitis herpetiformis  <response>: Ans. is a i.e., Bullous pemphgoid Important differential diagnosis of vesiculo bullous disordersVesicle Bullae Itching presentNo or minimal Itching o Moderate ItchingPain absentPain presento Intense ItchingPapulovesicular lesions on normal or erythmatous baseonExtensors knee, elbows, scapular region, buttocks, shoulder and sacral areaTense bullae on erythematous baseonLower part of body eg. lower abdomen, inner thigh, groins, intertiginous areao TenseVesicle bullae surrounding central erythema, erythematous halo Target lesiononface, acral partso FlaccidVesicle bullae onUpper part of bodyface, scalp, trunk necko Painful rash with vesicles along the distribution of a nerve dermatomeo Rash is unilateralo Suggestive featuresy Age - 20-40 yrsy BL symmetric distributiony Mucous membrane involvement - rarey Nickolskys sign -vey IgA in dermal papilla along basement membraneo Suggestive featuresy Sub epidermal bullaey Age - 60-80 yrsy Acantholysis absenty BL symmetric distributiony Mucous membrane not involvedy Nikolskys sign -vey C3 IgG along basement membrane DEJo Suggestive featuresy Age - children youngy Oral mucosa in 20y Starts acutelyy Bilateral symmetricaly Lasts 2 weeksy HO precipitating factors Drug, infection, UV radiationo Suggestive featuresy Intraepidermal bullaey Age - 30-60 yrsy Acantholysis vey Assy metric distributiony Involvement of mucous membraney Nikolsky rs sign vey IgG within epidermal intercellular substanceo Suggestive featuresy Age 45-70 yrsy History of pain, fever before the appearance of vesicley Rash appears before vesiclesy HO chicken pox in childhoodDermatitis herpetiformisBullous pemphigoidErythema multiformePemphigus vulgarisHerpes zosterNote - Acral parts - Palms, soles, dorsuin of hands feet distal parts of forearms legs. 