From the Guidelines
Acne is not primarily an infection, but rather an inflammatory disorder of the pilosebaceous unit, where bacteria play a role in its development. Acne forms when hair follicles become clogged with oil and dead skin cells, creating an environment where the bacteria Cutibacterium acnes (formerly Propionibacterium acnes) can thrive 1. These bacteria contribute to inflammation, but the initial cause is the clogged pore, not an infectious invasion. This is why acne treatments often include both antibacterial components (like benzoyl peroxide or topical antibiotics) to reduce bacteria and non-antibiotic treatments (like retinoids or salicylic acid) to prevent clogging 1.
Key Points to Consider
- The multifactorial pathogenesis of acne involves follicular hyperkeratinization, microbial colonization with Cutibacterium acnes, sebum production, complex inflammatory mechanisms, and genetic and nongenetic factors 1.
- Risk factors for acne development include increasing age during adolescence, family history of acne, and oily skin type 1.
- Acne has a significant impact on emotional functioning, social functioning, relationships, leisure activities, daily activities, sleep, school, and work, and is associated with increased risks of stigmatization, bullying, depression, anxiety, poor self-esteem, and suicidal ideation 1.
- The use of oral antibiotics for acne treatment is associated with antibiotic resistance, disruption of the normal flora, and increased rates of upper respiratory infection and pharyngitis 1.
Treatment Recommendations
- Topical benzoyl peroxide, retinoids, and/or antibiotics and their fixed-dose combinations are strongly recommended for acne treatment 1.
- Oral doxycycline is strongly recommended for acne treatment, while oral isotretinoin is strongly recommended for severe acne or acne that is resistant to other treatments 1.
- Limiting systemic antibiotic use and combining systemic antibiotics with benzoyl peroxide and other topical therapies are recommended as good clinical practices 1.
From the Research
Definition of Acne
Acne is a complex skin condition that involves inflammation of the pilosebaceous unit, which includes the hair follicle, sebaceous gland, and arrector pili muscle. It is characterized by the presence of comedones (blackheads and whiteheads), inflammatory lesions (papules, pustules, nodules, and cysts), and sometimes scarring 2.
Is Acne an Infection
While acne is not strictly an infection, it does involve the presence of bacteria, particularly Propionibacterium acnes (P. acnes), which plays a role in the development of inflammatory lesions. However, the primary cause of acne is not the bacteria itself, but rather the blockage of the hair follicle and the resulting inflammation 3, 4.
Role of Bacteria in Acne
P. acnes is a normal inhabitant of the skin and can contribute to the development of acne by:
- Breaking down sebum into fatty acids, which can irritate the skin and cause inflammation
- Producing pro-inflammatory factors that exacerbate the inflammatory response
- Contributing to the formation of comedones and inflammatory lesions 3, 4
Treatment of Acne
Treatment of acne typically involves a combination of topical and oral therapies, including:
- Topical retinoids, such as adapalene, which help to prevent comedone formation and reduce inflammation
- Benzoyl peroxide, which has antibacterial properties and can help to reduce the population of P. acnes on the skin
- Oral antibiotics, such as doxycycline, which can help to reduce inflammation and prevent scarring
- Hormonal therapies, such as combination oral contraception, which can help to regulate sebum production and reduce acne symptoms 5, 2, 6
Key Points
- Acne is a complex skin condition that involves inflammation of the pilosebaceous unit
- While acne is not strictly an infection, it does involve the presence of bacteria, particularly P. acnes
- Treatment of acne typically involves a combination of topical and oral therapies, including retinoids, benzoyl peroxide, and oral antibiotics.