Acne is also known as acne vulgaris. The common causes of acne include increased secretion of sebaceous glands, keratinization of sebaceous ducts in hair follicles, propagation of Propionibacterium acnes, and immune-inflammatory reactions. 1. Increased secretion of sebaceous glands: When androgens increase in the body due to various reasons, such as abuse of androgenic drugs and increased secretion of androgens during puberty, the sebaceous glands will be stimulated to secrete a large amount of oil. 2. Keratinization of follicular sebaceous gland ducts: Propionibacterium acnes can stimulate the formation of keratin at the follicular ducts, with excessive cell proliferation and keratinization, leading to blockage or narrowing of follicular openings, which affects the discharge of sebaceous glands and the formation of acne. 3. Proliferation of Propionibacterium acnes: excessive proliferation of Propionibacterium acnes can lead to inflammation of the hair follicle and the surrounding area, resulting in acne. 4. Immuno-inflammatory response: Sebaceous gland overflow leads to excessive proliferation of Propionibacterium acnes, prompting the production of inflammatory factors and inducing an inflammatory response. Acne should be treated promptly and in a standardized manner.