This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Dental
[{'content': 'A male patient presents with patchy loss of hair on scalp, eyebrows and beard. He also gives history of rapid graying of hair in a few areas. The likely diagnosis is – \nSelect and explain. \nA. Alopecia areata, B. Anagen effluvium, C. Telogen effluvium, D. Androgenic alopecia', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Information provided in this question are -\n\n\nPatchy hair loss (focal alopecia)\nHair loss on scalp, eyebrows and beard\nHistor of rapid graying of hair\n\n\nAll suggest the diagnosis of Alopecia areata -\n\n\nIn Alopecia areata, hair loss is patchy and well circumcirbed.\nAlopecia areata most commonly involves scalp but any hair bearing skin e.g., beard, eyebrows, and eye lashes\xa0can be involved.\nThe characteristic feature of alopecia areata is sparing of grey/white (non-pigmented) hair and preferential involvement of block/brown (pigmented) hair. If alopecia progress rapidly, it appears as rapid greying of hair\xa0as black hair are shed and grey hair are spared → Going gray/white overnight phenomenon.', 'role': 'assistant'}]