What is the Nikolsky sign?

• A. Slippage of the epidermis from the dermis with slight rubbing/pressure
• B. Blanching of the skin with pressure
• C. Increased capillary refill time
• D. Absence of bullae on examination

Answer: (A)

The Nikolsky sign is the slippage or shearing of the outer skin layer from the underlying dermis when a small area is gently rubbed or pressed. This happens because the epidermal cells lose their adhesion to one another (acantholysis) in certain blistering diseases, most classically pemphigus vulgaris, and can occur in other conditions like toxic epidermal necrolysis. So the described finding—epidermal separation with slight rubbing/pressure—best fits this sign.

The other options don’t describe this phenomenon: blanching with pressure relates to blood flow and vasculature rather than epidermal cohesion; increased capillary refill time is a perfusion measure; absence of bullae doesn’t reflect the mechanical separation of the epidermis seen with Nikolsky.