Management of acne: Canadian clinical practice guideline.

Acne is one of the most burdensome dis­ eases globally.1,2 Its prevalence among those aged 12 to 24 years is estimated to be 85%, although it can persist beyond young adulthood despite treatment.3–5 Acne can adversely affect quality of life6–13 and may lead to emotional distress and physical scarring.14,15 The clinical presentation of acne (Figure 1) varies from primarily comedonal to mixed comedonal and inflammatory acne.16 Since the last Canadian acne guideline was published in 2000,17 evidence for multiple addi­ tional treatments has been published. Thus, there was an unmet need for an updated, systematic­ ally developed, evidence­based Canadian acne clinical practice guideline. This guideline pro­ vides recommendations adapted to the Canadian health care system to assist Canadian health care providers in the diagnosis of acne vulgaris, including investigations where appropriate; it also provides updated information on the patho­ genesis of acne, outlines methods for evaluating acne severity, provides evidence­based guidance on treatments for acne vulgaris and recommends treatments for acne according to severity. To support clinical practice, recommenda­ tions are made for three categories of acne sever­ ity: comedonal acne, which consists of small white papules (closed comedones) or grey–white papules (open comedones), which are due to complete or partial ductal occlusion, respec­ tively, and sebum accretion (Figure 1A); mild­ to­moderate papulopustular acne, which is char­ acterized by inflammatory lesions that are mostly superficial (Figures 1B and 1C); and severe acne, consisting of deep pustules and/or nodules, which may be painful, may extend over large areas and can lead to tissue destruction (Figures 1D and 1E). A subtype of severe acne, conglo­ bate acne, is rare and consists of extensive inflammatory papules, nodules and cysts, which can lead to disfiguring scars.16 Scope