Grattage test is used for-: (A) Tinea capitis, (B) Lichen planus, (C) Pemphigus vulgaris, (D) Psoriasis
Answer is D. Grattage test: scales in a psoriatic plaque can be accentuated by scraping with a glass slide. signe de la tache de bougie: characteristic coherence of scales as if one scratches a wax candle