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
Which of the following is the drug of choice in the treatment of nodulo cystic acne? 
Select and explain. 
A. Systemic steroids, B. Isotretinoin, C. Estrogen, D. Benzoylperoxide
B: Isotretinoin
Answer: B: Isotretinoin 
Explanation: Nodulocystic acne is a severe form of acne affecting face, chest and back. It is characterised by multiple inflammed and uninflammed nodules with great tendency for scar formation. Isotretinoin is the drug of choice of nodulocystic acne. It is absolutely contraindicated in pregnancy due to its teratogenic effects.