What causes acne? - A to Z Dermatology
The causes of acne are linked to the changes that take place as young people mature from childhood to adolescence (puberty). The hormones that cause physical maturation also cause the sebaceous (oil) glands of the skin to produce more sebum (oil). The hormones with the greatest effect on sebaceous glands are androgens (male hormones), which are present in females as well as males, but in higher amounts in males.
Sebaceous glands are found together with a hair shaft in a unit called a sebaceous follicle. During puberty, the cells of the skin that line the follicle begin to shed more rapidly. In people who develop acne, cells shed and stick together more so than in people who do not develop acne. When cells mix with the increased amount of sebum being produced, they can plug the opening of the follicle. Meanwhile, the sebaceous glands continue to produce sebum, and the follicle swells up with sebum.
In addition, a normal skin bacteria called P. acnes, begins to multiply rapidly in the clogged hair follicle. In the process, these bacteria produce irritating substances that can cause inflammation. Sometimes, the wall of the follicle bursts, spreading inflammation to the surrounding skin. This is the process by which acne lesions, from blackheads to pimples to nodules, are formed.