This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Skin
[{'content': "Casal's necklace is a feature of? \nSelect and explain. \nA. Addison disease, B. Pellagra, C. Dermatomyositis, D. SLE", 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Pellagra* The Casal collar or Casal necklace is a clinical sign in which there is an erythematous pigmented skin rash partly or completely encircling the lower part of the neck (dermatomes C3 and C4). It is seen in patients with pellagra.", 'role': 'assistant'}]