<prompt> A 24 years old female has flaccid bullae in the skin and oral erosions. Histopathology shows intraepidermal acantholytic blister. The most likely diagnosis is :Pemphigoid.Erythema multiforme.Pemphigus vulgaris.Dermatitis herpetiformis.  <response>: Ans. is c i.e. pemphigus vulgaris Bullae involving oral mucosa with intraepidermal lesions acantholysis is characteristic of pemphigus.Here is a Dd of commonly asked vesico bullous disordersVesiculobullous disordersINFECTIOUSHerpes SimplexCluster of vesicles usually on facePainfulRecurrentTwo types-Type I -Seen in childhood gingivostomatitis, fever, vesicles on lipsType II -In young adults after sexual contact usually involves genitaliaHerpes ZosterVesicular eruption occurs in dermatomal pattern. Thoracic dermatome is the most commonly involved 50Involvement of ophthalmic division of trigeminal N.Painful and tender23 of patients over 40 yrs of ageNON-INFECTIOUS PemphigusVesicles are seen on the upper part of body. Trunk limbs.Lesions are non itchy and painlessOral mucosa involvement in 50 cases.Lesions are intraepidermalAcantholysis presentNikolsky sign presentAge Group 40-50 Pemphigoid 1. Vesicles seen on the lower part of body, limbs trunk.2; Lesions are non itchy and painlessOral mucosa not involvedLesions are subepidermalAcantholysis absentNicolasky sign absentAge Group 60-80 Dermatitis HerpetiformisVesicles seen on extensor surfaceVesicles are itchy and painlessVillous atrophy usualLesions are subepidermalYoung adults are involved Erythema multiformeCharacteristic vesicular lesions on hands and feet target lesionnon itchy and painless.face and upper limbs involvedmucosal involvement can be seen So the crux is Painful lesions are seen in-. Herpes infection. Painless lesions are seen in-Dermatitis herpetiformis Pemphigoid Pemphigus Erythema multiforme Dermatomal involvement-. Herpes zoster Itchy lesions-Dermatitis herpetiformis Intraepidermal-. Herpes and pemphigus Subepidermal-. Dermatitis herpetiformisPemphigoid Erythema multiforme 