From the Guidelines
An infection refers to the invasion and multiplication of harmful microorganisms in the body, while a disease is the resulting condition that causes specific symptoms and signs due to the body's response to infection or other causes. Acne vulgaris illustrates this distinction well. In acne, the infection component involves Cutibacterium acnes (formerly Propionibacterium acnes) bacteria colonizing hair follicles and sebaceous glands, as noted in the guidelines of care for the management of acne vulgaris 1. These bacteria thrive in the anaerobic environment created by excess sebum production and follicular hyperkeratinization. However, the disease of acne vulgaris encompasses more than just this bacterial presence. It includes the inflammatory response to these bacteria (resulting in papules, pustules, and nodules), the hormonal factors that increase sebum production, genetic predisposition, and the resulting clinical manifestations like comedones, inflammation, and potential scarring.
Some key points to consider in the management of acne vulgaris include:
- The use of topical benzoyl peroxide, retinoids, and/or antibiotics, as well as their fixed-dose combinations, as recommended by the guidelines 1.
- The importance of limiting systemic antibiotic use and combining systemic antibiotics with benzoyl peroxide and other topical therapies, as noted in the guidelines 1.
- The role of hormonal therapies, such as combined oral contraceptives and spironolactone, in the treatment of acne vulgaris, as discussed in the guidelines 1.
- The need to consider the potential risks and benefits of different treatments, including the risk of antibiotic resistance and other adverse effects, as noted in the guidelines 1.
This explains why acne treatment often targets multiple aspects: antibiotics address the bacterial infection component, while retinoids, hormonal therapies, and other treatments address the broader disease process by regulating sebum production, reducing inflammation, and normalizing follicular keratinization. Understanding this distinction helps explain why simply killing bacteria isn't sufficient to fully treat acne, as the disease involves multiple pathological processes beyond just the infectious component, as discussed in the guidelines 1.
From the Research
Differentiation between Infection and Disease
- An infection refers to the invasion and colonization of a host organism by a foreign agent, such as a bacterium, virus, or fungus, which can cause harm to the host 2, 3.
- A disease, on the other hand, is a disorder of structure or function that affects part or all of an organism, resulting from a combination of genetic, environmental, and lifestyle factors 4, 5.
- Acne vulgaris is an example of a disease that involves inflammation of the pilosebaceous unit of the skin, which can be triggered by a combination of factors, including bacterial colonization, hormonal changes, and genetic predisposition 2, 6.
Acne Vulgaris as an Example
- Acne vulgaris is a chronic skin disease that affects approximately 9% of the population worldwide, with a higher prevalence among adolescents and young adults 2, 3.
- The disease is characterized by the formation of comedones, inflammatory lesions, and scarring, which can have a significant impact on quality of life and self-esteem 2, 3.
- While Cutibacterium acnes (formerly known as Propionibacterium acnes) is a bacterium that is commonly associated with acne, the disease is not solely caused by a bacterial infection, but rather by a complex interplay of factors, including hormonal changes, sebum production, and inflammation 3, 6.
Treatment of Acne Vulgaris
- Treatment of acne vulgaris typically involves a combination of topical and systemic therapies, including retinoids, benzoyl peroxide, antibiotics, and hormonal agents 2, 4, 5.
- Topical retinoids are a first-line treatment for acne vulgaris, and have been shown to be effective in reducing lesion counts and improving quality of life 5.
- Systemic antibiotics, such as doxycycline and minocycline, may be used in combination with topical therapies for more severe cases of acne, but their use is limited due to concerns about antibiotic resistance 3, 6.