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: Skin
A girl about to marry has comedonal acne. Drug to treat such a case is: March 2013 
Select and explain. 
A. Topical antibiotic, B. Benzoyl peroxide, C. Retinoids, D. Estrogen
C: Retinoids
Answer: C: Retinoids 
Explanation: Ans. C i.e. RetinoidsRetinoids are mainly comedolyticAcneComedones are characteristic of: Acne vulgarisComedones are:- Small cysts,- formed in hair follicles,- due to blockage of the follicular orifice- by the retention of sebum and keratinous materialAcen vulgaris is caused by: Obstruction of pilosebaceous duct Nodulocystic acne (NA)Treatment of NA: Isotretinonin (synthetic retinoic acid)