This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Vestibulobullous disorders, Subject name: Dental
[{'content': "Nikoisky's sign is positive in \nSelect and explain. \nA. Pemphigus, B. Dermatitis herpatiformis, C. Pemphigoid, D. Rubella", 'role': 'user'}, {'content': "Answer: A \nExplanation: Nikolsky's sign : Development of an erosion on surrounding normal skin following shearing pressure .Though this sign is characteristic for pemphigus group of disorders is not specific and can be elicited in burns and other skin disorders. Page no. 281 Reference IADVL's concise textbook of dermatology", 'role': 'assistant'}]