A 40 year old male repoed with recurrent episodes of oral ulcers, large areas of denuded skin and flacid vesiculo-bullous eruptions. Which is the most impoant bed-side investigation helpful in establishing the diagnosis -: (A) Gram staining of the blister fluid, (B) Culture and sensitivity, (C) Skin biopsy and immunoflurescence, (D) Tzanck smear from the floor of bulla
Answer is D. D. i.e. Tzank smear