Mechanism-based treatment of acne vulgaris: the value of combination therapy.

Acne vulgaris has multiple pathogenic mechanisms that act in concert to produce disease. Effective therapy addresses more than one pathogenic factor to speed resolution of disease. Typically, retinoids are used to inhibit comedo formation and an antibacterial is used to suppress Propionibacterium acnes (P. acnes). Using combinations of agents can enhance efficacy, but increase side effects. Therefore, the tolerability of a topical retinoid is important. Strategies to enhance retinoid tolerability include the use of new retinoids such as adapalene, new delivery systems such as the tretinoin microsphere delivery system, or alternative dosing schedules such as short contact or every other day (QOD).