Bullous pemphigoid is an autoimmune subepidermal blistering disorder of the elderly, distinguished within the differential diagnosis of bullous skin disease by a characteristic clinical constellation: a prodromal phase of pruritic urticarial/erythematous patches preceding tense bullae, absence of mucosal involvement, absence of systemic/constitutional symptoms, and a negative Nikolsky sign reflecting an intact epidermis with the blister plane located below it. This diagnostic reasoning belongs to dermatology and illustrates the broader principle that the level of skin cleavage (subepidermal versus intraepidermal), presence or absence of mucosal involvement, sun-exposure distribution, and systemic features together differentiate the major bullous disorders (bullous pemphigoid, pemphigus vulgaris, Stevens-Johnson syndrome/toxic epidermal necrolysis, porphyria cutanea tarda, staphylococcal scalded skin syndrome).
Bullous pemphigoid is an autoimmune subepidermal blistering disorder of the elderly, distinguished within the differential diagnosis of bullous skin disease by a characteristic clinical constellation…