A 24 years old female has flaccid bullae in the skin and oral erosions. Histopathology shows intraepidermal acantholytic blister. The most likely diagnosis is :

Ans. is 'c' i.e. pemphigus vulgaris Bullae involving oral mucosa with intraepidermal lesions & acantholysis is characteristic of pemphigus.Here is a D/d of commonly asked vesico bullous disordersVesiculobullous disordersINFECTIOUSHerpes SimplexCluster of vesicles usually on face*Painful*Recurrent*Two types-Type I -Seen in childhood gingivostomatitis*, fever, vesicle's 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 (50%)*Involvement of ophthalmic division of trigeminal N.*Painful and tender*2/3 of patients over 40 yrs of ageNON-INFECTIOUS PemphigusVesicles are seen on the upper part of body. Trunk > limbs.Lesions are non itchy and painless*Oral mucosa involvement* in 50% cases.Lesions are intraepidermal*Acantholysis present*Nikolsky sign present*Age Group 40-50 Pemphigoid 1. Vesicles seen on the lower part of body, limbs >trunk.*2; Lesions are non itchy and painless*Oral mucosa not involved*Lesions are subepidermal*Acantholysis absent*Nicolasky sign absent*Age Group 60-80 Dermatitis HerpetiformisVesicles seen on extensor surface*Vesicles are itchy and painless*Villous atrophy usual*Lesions are subepidermal*Young adults are involved Erythema multiformeCharacteristic vesicular lesions on hands and feet (target lesion)*non 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