Acne is a disease caused by a variety of factors, which may be due to blockage of the follicular opening, abnormal androgen levels, and propagation of Propionibacterium acnes. 1. Clogged follicles: Abnormal keratinization of the cells around the hair follicles causes the follicles to become narrow, clogged, and small, so sebum cannot be discharged normally and accumulates in the follicles to form pimples, leading to the formation of acne. 2. Abnormal androgen levels: Increased levels of androgen in the body cause sebaceous glands to enlarge and sebum secretion to increase, and the shedding of cells and oil clogs pores, resulting in the formation of acne. 3. Propionibacterium acnes reproduction: This bacterium usually exists in the hair follicles and sebaceous glands of the skin. If the sebaceous glands increase their secretion, the composition of sebum is suitable for the growth and reproduction of Propionibacterium acnes, which induces an inflammatory reaction. In addition, factors such as heredity, irrational use of skin care products, overwork and mental stress can increase the risk of acne. Acne should be seen promptly and treated actively to avoid delays.