A 85-year-old female developed multiple blisters on trunk and thighs. Nikolsky's sign negative. The lesions came on and off. The most probable diagnosis is:

Ans. B. Bullous PemphigoidBULLOUS PEMPHIGOID (BP)a. Autoimmune subepidermal blistering disease.b. The major histocompatibility complex class II allele HLA-DQ1*0301 is prevalent.c. Usually seen in the elderly.d. Lesions typically consist of tense blisters on either normal-appearing or erythematous skin.e. Usually distributed over the lower abdomen, groin, and flexor surface of the extremities.f. Oral mucosal lesions are found in 10to40% of patients.g. Pruritus may be nonexistent or severe.h. Non traumatized blisters heal without scarring.i. As lesions evolve, tense blisters tend to rupture and be replaced by flaccid lesions or erosions with or without surmounting crust.j. BP do not have an increased incidence of malignancy.k. Investigations:i. Biopsies of early lesional skin demonstrate subepidermal blisters.ii. Direct immunofluorescence microscopy of normal-appearing perilesional skin shows linear deposits ofiii. IgG- and/or C3 in the epidermal basement membrane.iv. In BP, circulating autoantibodies recognize 230- and 180-kDa Hemidesmosome-associated proteins in basal keratinocytes .l. Rx:i. The mainstay of treatment is systemic glucocorticoids.ii. Patients will usually respond to prednisone, 40to60mg/d.iii. In some instances, azathioprine (1to2mg/kg per day), mycophenolate mofetil (20to35mg/kg per day), or cyclophosphamide (1to2mg/kg per day) are necessary adjuncts.NIKOLSKY SIGN is seen in:a. Pemphigus vulgarisb. Staphylococcal skin scalded syndromec. Stevens Johnson Syndromed. TENe. Leukemiaf. Herpesg. Epidermolysis bullosa congenita