What is the primary cause of acne vulgaris?

Acne vulgaris primarily arises as a result of hormonal changes, which play a significant role in the development of this skin condition. During puberty, for example, increased levels of androgens can lead to hypersecretion of sebum from the sebaceous glands and can also cause an increase in keratinization of the hair follicles. This excessive production of sebum combined with clogged hair follicles creates an ideal environment for the proliferation of bacteria, leading to inflammation and the formation of acne lesions.

The role of hormonal changes is not limited to puberty; similar fluctuations can occur during the menstrual cycle, pregnancy, and with conditions such as polycystic ovary syndrome (PCOS). The effect of hormones on sebaceous gland activity and follicular keratinization directly contributes to the increased incidence of acne in certain populations.

While excessive keratin production, bacterial infection, and sun exposure can influence the severity and appearance of acne, they are not the primary cause. Excessive keratinization may contribute to clogged pores, and bacterial infection, particularly by Propionibacterium acnes, can exacerbate existing lesions, but these processes are typically secondary to the influence of hormonal changes that initiate the acne cascade. Sun exposure might even have a temporary drying effect on