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': "A 50-year-old woman develops pink macules and papules on her hands and forearms in association with a sore throat. The lesions are targetlike, with the centers a dusky violet. A diagnosis of erythema multiforme is made. The most important information obtained from this patient's history is \nSelect and explain. \nA. The patient has been using tampons, B. The patient is taking phenytoin, C. The patient has never had measles, D. No other family members have a sore throat", 'role': 'user'}, {'content': 'Answer: B \nExplanation: (b) Source: (Braunwald, 15/e, pp 337-339.) Erythema multiforme is often caused by drugs. It is most important to identify the offending agent. Phenytoin can induce erythema multiforme, so this information is critical. Sulfa drugs, barbiturates, and penicillin can also be causes. The rash, with its target lesions, should not be confused with toxic shock or measles. The sore throat is likely to be a symptom from the process itself, suggesting involvement of the oral mucosa.', 'role': 'assistant'}]