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Nikolsky Sign Mechanism — NDEB AFK MCQ

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ModerateOral PathologyNikolsky Sign MechanismNDEB AFK

The Nikolsky sign is performed by applying gentle lateral pressure to apparently normal mucosa. A positive result (epithelial sloughing or blister formation) indicates disruption of which structure?

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Correct answer: E — Intercellular adhesion between epithelial cells (desmosomal attachment)

A positive Nikolsky sign indicates disrupted intercellular adhesion (desmosomal failure) when the epithelium slides on lateral pressure. In pemphigus vulgaris, autoantibodies against desmoglein 3 (and sometimes desmoglein 1) cause acantholysis — loss of desmosomal adhesion between keratinocytes. This allows the epithelium to shear easily. Nikolsky sign can also be positive in pemphigoid (disrupted hemidesmosomal/BM attachment) and other vesiculobullous conditions, but is most classically associated with pemphigus vulgaris.

Reference: Neville – Oral and Maxillofacial Pathology, 4th ed., 2016