This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: S.T.D., Subject name: Skin
[{'content': 'A patient after a trip to Bangkok has developed fever and perioral vesicles, diagnosis is: \nSelect and explain. \nA. Herpes simplex, B. Impetigo, C. Molluscum contagiosum, D. Bullous pemphigoid', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (a) Herpes simplex.* Notice the grouped vesicles with lesions showing umbilication which is a presentation of primary herpes gingivo- stomatitis.* Primary episode is quite distressing for the patient with fever constitutional symptoms and small eroded painful lesions on lips oral mucosa and perioral area.* Impetigo presents with honey colored crusts on the skin and is ruled out.* Molluscum contagiosum is caused by pox virus infection and produces crops of dome shaped papules with umbilicated center on body which are asymptomatic.* In the question patient has fever and location of vesicles is peri-oral and trip to a place known for sex tourism which favors diagnosis of herpes simplex.', 'role': 'assistant'}]