Which medication is the most suitable initial treatment for a 15-year-old male with mild comedonal acne?

Topical retinoids are the most suitable initial treatment for a 15-year-old male with mild comedonal acne. Comedonal acne is characterized by the presence of open (blackheads) and closed (whiteheads) comedones, and topical retinoids work effectively to normalize the shedding of skin cells within hair follicles, thereby preventing the formation of these comedones. They help in unclogging pores, reducing inflammation, and promoting skin cell turnover, which are essential in managing mild acne, especially in adolescents.

In contrast, isotretinoin is typically reserved for severe acne cases due to its powerful effects and potential side effects, making it inappropriate for initial treatment of mild acne. Oral erythromycin is not the first line for milder cases since acne treatments generally focus on topical agents due to fewer side effects and better localized action. While reassurance can play a role in managing expectations around acne, it does not provide a direct therapeutic intervention, hence is not the most appropriate initial treatment option when an effective topical medication is available.