This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Skin, Subject name: Pharmacology
All trans retinoic acid is used topically for - 
Select and explain. 
A. Acne vulgaris, B. Lupus vulgaris, C. Alopecia areata, D. Androgenic alopecia
A: Acne vulgaris
Answer: A: Acne vulgaris 
Explanation: Ans. is 'a' i.e., Acne vulgaris * All-trans retinoic acid (Tretinoin) is used topically, while 13-cis retinoic acid (Isotretinoin) is given orally for acne.