system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
Which is a specific lesion of acne vulgaris?
assistant
The correct answer is  Ans. c. ComedonesComedones are pathognomonic of acne.Comedones are the keratin plugs of the pilosebaceous ducts.When the keratin plug is inside the follicle, it is called closed comedone (whitehead).When the keratin plug is exposed to the environment, it turns black and is known as open comedone (blackhead).Comedonal lesions are the earliest lesions of acne.