From the Guidelines
Acne is not considered an infection because it's primarily an inflammatory condition caused by multiple factors rather than a single infectious agent. While bacteria (particularly Cutibacterium acnes) play a role in acne development, the condition begins with excess oil production, abnormal skin cell shedding, and hormonal influences that lead to clogged pores. These clogged pores create an environment where naturally occurring skin bacteria can proliferate, triggering an inflammatory response. Unlike true infections which involve pathogenic microorganisms invading and multiplying in tissue, acne involves normal skin flora becoming problematic only when trapped in follicles. This distinction explains why acne treatments often include both anti-inflammatory medications (like benzoyl peroxide or retinoids) and antimicrobials (like topical clindamycin or oral antibiotics), rather than just antibiotics alone. For effective acne management, a comprehensive approach addressing oil production, cell turnover, inflammation, and bacterial factors is needed, typically involving consistent use of topical treatments and sometimes oral medications depending on severity.
Key Factors in Acne Development
- Excess oil production
- Abnormal skin cell shedding
- Hormonal influences
- Clogged pores
- Proliferation of normal skin bacteria (Cutibacterium acnes)
Treatment Approach
- Comprehensive approach addressing multiple factors
- Topical treatments (e.g., benzoyl peroxide, retinoids, antibiotics)
- Oral medications (e.g., doxycycline, isotretinoin) for severe cases
- Limiting systemic antibiotic use to reduce resistance and complications, as recommended by recent guidelines 1
Recent Guidelines
The most recent guidelines for acne management, published in 2024, recommend a multimodal approach combining multiple mechanisms of action, including topical benzoyl peroxide, retinoids, and antibiotics, as well as oral doxycycline for severe cases 1. These guidelines also emphasize the importance of limiting systemic antibiotic use and using concomitant benzoyl peroxide to prevent antibiotic resistance.
Evidence-Based Recommendations
The guidelines provide strong recommendations for topical benzoyl peroxide, retinoids, and antibiotics, as well as oral doxycycline, based on moderate certainty of evidence 1. Conditional recommendations are made for other treatments, such as clascoterone, salicylic acid, and azelaic acid, based on varying levels of evidence.
Conclusion Not Provided as per Guidelines
Instead, the key points are summarized above, with a focus on the most recent and highest quality evidence 1.
From the Research
Definition of Acne
Acne is a chronic inflammatory condition of the pilosebaceous follicles, characterized by excessive sebum production, hyperkeratinization of pilosebaceous follicles, hyperproliferation of Propionibacterium acnes (P. acnes), and inflammation 2.
Pathophysiology of Acne
The pathophysiology of acne involves four important factors:
- Excessive sebum production
- Hyperkeratinization of pilosebaceous follicles
- Hyperproliferation of P. acnes
- Inflammation 2. Acne is not considered an infection in the classical sense, as it is not caused by a single pathogen, but rather by a combination of factors, including the overgrowth of P. acnes, a normal inhabitant of the skin 3, 2, 4.
Treatment of Acne
Treatment of acne typically involves a combination of topical and systemic therapies, including:
- Topical retinoids
- Benzoyl peroxide
- Azelaic acid
- Antibiotics
- Hormonal therapies 3, 2, 5, 6, 4. The goal of treatment is to reduce inflammation, prevent scarring, and improve quality of life 2, 6.
Role of P. acnes in Acne
P. acnes plays a key role in the development of acne, as it contributes to the inflammation and comedone formation characteristic of the condition 3, 2, 4. However, acne is not considered an infection because P. acnes is a normal inhabitant of the skin, and its overgrowth is just one of the many factors that contribute to the development of acne 2.