第 39 題

Bravo, you managed to correctly identify a negative Nikolsky sign. Don't get too excited; it's a fundamental concept, though alarmingly often misunderstood. The Nikolsky sign, for those paying attention in class, is a direct indicator of compromised integrity at the Desmosomes within the epidermis or the epidermal-dermal junction. A positive sign, as seen in Pemphigus or SSSS, means the damage is intraepidermal, making the structure so fragile that a mere touch causes detachment. Hardly rocket science. Conversely, a negative sign – your correct answer, by the way – is characteristic of Bullous pemphigoid. Here, the antibodies target the Hemidesmosomes beneath the epidermis. This creates a subepidermal blister with an intact epidermal roof, rendering it significantly more robust and resistant to lateral pressure. It’s not about rote memorization; it's about connecting the anatomical pathology to the physical manifestation. This is a Medium difficulty question, precisely to distinguish superficial recall from actual comprehension. Don't mistake luck for mastery.