Desquamative gingivitis with positive Nikolsky sign

Correct answer: B. Aphthous ulceration

• A. Mucous membrane (cicatricial) pemphigoid is the single most common cause of desquamative gingivitis and is Nikolsky-positive (subepithelial split).
• B. Correct. Recurrent aphthous ulceration produces discrete, punched-out ulcers with an erythematous halo on NON-KERATINISED, NON-ATTACHED mucosa. It does not cause desquamative gingivitis and is Nikolsky-NEGATIVE, so it cannot explain this presentation.
• C. Erosive lichen planus is the third member of the classic desquamative gingivitis triad and can also give a positive Nikolsky sign.
• D. Pemphigus vulgaris is a classic cause of desquamative gingivitis with a positive Nikolsky sign (intraepithelial split, suprabasilar acantholysis).

Note: The desquamative gingivitis triad worth memorising: MUCOUS MEMBRANE PEMPHIGOID, PEMPHIGUS VULGARIS, and EROSIVE LICHEN PLANUS.

Correct answer: A. An abrasive prophy jet / air-polishing unit

• A. Correct. The epithelium separates under minimal force, so any abrasive or high-pressure instrumentation — air polishing, prophy paste under pressure, forceful retraction — will strip the mucosa and create iatrogenic erosions. Care is atraumatic.
• B. ALCOHOL-FREE mouthwash is specifically what you WANT: alcohol-containing rinses burn denuded mucosa and worsen symptoms.
• C. A mouth mirror is unavoidable and acceptable; it is used gently with minimal tissue retraction.
• D. Scaling is still required to control plaque, which markedly worsens desquamative gingivitis — it is performed gently rather than avoided.

Correct answer: D. Corticosteroids

• A. Antifungals treat candidiasis — a possible SUPERINFECTION during steroid therapy, but not the primary disease.
• B. These are not primarily bacterial conditions; antibiotics do not address the autoantibody-mediated epithelial separation.
• C. Antivirals are for herpetic disease, which produces clustered vesicles on keratinised mucosa, not diffuse desquamation with a positive Nikolsky sign.
• D. Correct. All three desquamative gingivitis conditions are IMMUNE-MEDIATED, so treatment is immunosuppression — topical high-potency corticosteroids (often in a custom tray for gingival lesions) for localised disease, systemic corticosteroids ± steroid-sparing agents for severe or widespread disease.

Correct answer: D. Perilesional biopsy

• A. Culture and sensitivity is for infectious disease, which this is not.
• B. Excising the ulcer bed removes exactly the epithelium that was already lost — the diagnostic information sits at the margin.
• C. Brush biopsy samples surface cells only and cannot demonstrate the level of epithelial separation or the immunofluorescence pattern.
• D. Correct. Vesiculobullous disease requires a PERILESIONAL biopsy — normal-appearing tissue immediately ADJACENT to the lesion — so that intact epithelium is present for direct immunofluorescence. Sampling the ulcer itself yields only denuded, non-diagnostic tissue.

Note: Send the perilesional specimen in Michel's medium for DIRECT IMMUNOFLUORESCENCE, and a second specimen in formalin for routine H&E.