Skin General d400f5d6 Which of the following is the most common side effect of Isotretinoin used for acne vulgaris? A Facial erythema B Xerosis C Hair loss D Cheilitis High-Yield Explanation Cheilitis is the most common side effect of isotretinoin. Ref: Rook Textbook of Dermatology, 8th edition, Page 42.64