Correct answer : b
Bullous Pemphigoid :
It is a chronic autoimmune Subepidermal NON acantholytic blistering disorder where IgG autoantibodies are formed against bullous pemphigoid antigen 1 & 2 (BP 180/BPAG 2 > BP 230 / BPAG 1).
Clinical features :
Elderly (60-80years) with itchy tense haemorrhagic blisters (overlying roof settles down , sticking to the base which later heals with scar or milia formation , having perilesional urticarial skin with erythema .
Lesions have predilection for flexural areas on the thigh , groin , trunk & axilla . blisters may heal with hypopigmentation.
Nikolsky sign negative.