Acne treatments: future trajectories.

Current acne treatments present several limitations, posing the need for new effective therapies for long-term administration for recalcitrant or relapsing acne. Key players in acne that may emerge as targets for future acne treatments include the cutaneous loss of diversity of Cutibacterium (formerly Propionibacterium) acnes phylotypes and the insulin-like growth factor-1 signalling pathway. New data about the loss of diversity of microbiota in acne provides the rationale for the potential use of oral or topical probiotics. Another therapeutic approach to modulate the microbiota could be topical formulation of C. acnes bacteriophages to target specifically the pathogenic 'acnegenic' C. acnes phylotypes. Insulin-sensitizing agents such as metformin, myo-inositol and d-chiro-inositol represent promising agents, but to date there have been only limited studies and much heterogeneity in the methods of assessing acne efficacy outcomes. Moving towards a holistic approach for patients with acne is the future, by taking into account both internal and external factors, such as pollution, stress, acne family history, age, smoking habits and diet, and addressing quality of life and the psychological impact of acne.