Which condition is characterized by intraepidermal blisters and a positive Nikolsky sign?

Which condition is characterized by intraepidermal blisters and a positive Nikolsky sign?

• A. Erythema multiforme
• B. Pemphigus vulgaris
• C. Morbilliform eruption
• D. Discoid lupus

Answer: (B)

In pemphigus vulgaris, the problem is loss of cell-to-cell adhesion within the epidermis due to autoantibodies attacking desmosomes (desmoglein 3, and sometimes desmoglein 1). This acantholysis creates blisters that form inside the epidermal layer (intraepidermal blistering), and because the epidermis becomes fragile, even light rubbing or pressure can cause sheets of skin to separate—producing a positive Nikolsky sign. Clinically, you often see flaccid bullae that rupture easily and mucosal involvement. Other conditions shown typically produce blisters beneath the epidermis (subepidermal) or lack blistering altogether, and they usually don’t exhibit a positive Nikolsky sign.

In pemphigus vulgaris, the problem is loss of cell-to-cell adhesion within the epidermis due to autoantibodies attacking desmosomes (desmoglein 3, and sometimes desmoglein 1). This acantholysis creates blisters that form inside the epidermal layer (intraepidermal blistering), and because the epidermis becomes fragile, even light rubbing or pressure can cause sheets of skin to separate—producing a positive Nikolsky sign. Clinically, you often see flaccid bullae that rupture easily and mucosal involvement. Other conditions shown typically produce blisters beneath the epidermis (subepidermal) or lack blistering altogether, and they usually don’t exhibit a positive Nikolsky sign.