What organism is primarily responsible for causing acne?

Propionibacterium acnes is a gram-positive bacterium that resides within the sebaceous glands of the skin. It plays a crucial role in the development of acne vulgaris, which is primarily due to its ability to thrive in the oily environment of blocked hair follicles. As the hair follicles become clogged with excess oil and dead skin cells, the population of Propionibacterium acnes can proliferate. This leads to inflammation and the formation of acne lesions.

The inflammatory response triggered by the presence of this bacterium contributes significantly to the redness, swelling, and pus associated with acne. The organism promotes an immune response that results in the characteristic symptoms of acne, such as papules and pustules.

Understanding the role of Propionibacterium acnes in acne formation is essential for developing effective treatment strategies that target not only the symptoms but also the underlying microbial factors contributing to the condition.