Reduces acne lesions: Topical erythromycin can decrease pustules and papules by curbing bacterial overgrowth and inflammation in follicles. Dermatology trials show it improves mild to moderate acne, especially in combination with topical benzoyl peroxide (to prevent resistance). It helps unclog pores over time and calms redness associated with acne. (Efficacy may diminish if bacteria become resistant, hence often combined with other agents.)