Nikolsky Sign Technique — MFDS Part 1 MCQ
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Correct answer: B — Applying gentle tangential pressure to normal-appearing perilesional mucosa, causing the superficial epithelium to shear away
The correct answer is B. A positive Nikolsky sign is produced by gentle horizontal or tangential pressure on clinically normal-appearing mucosa near a lesion, causing the superficial epithelium to shear or peel away. In pemphigus vulgaris, this reflects loss of cohesion between keratinocytes due to acantholysis. Option E describes the bulla-spread or Asboe–Hansen sign, in which pressure on an existing blister extends it. Option C describes collection of a cytological smear, while option D is part of the confirmatory diagnostic investigation using direct immunofluorescence. Puncturing a vesicle, as in option A, does not elicit Nikolsky sign.
Reference: Mignogna MD, Fortuna G, Leuci S, et al. Nikolsky's sign on the gingival mucosa: a clinical tool for oral health practitioners. Journal of Periodontology. 2008;79(12):2241–2246. https://pubmed.ncbi.nlm.nih.gov/19053912/