What is the primary cause of acne vulgaris?

Acne vulgaris is primarily caused by hormonal changes, particularly those that occur during adolescence and puberty. These hormonal fluctuations lead to increased oil production in the sebaceous glands, which can clog hair follicles and create an environment conducive to the growth of acne-causing bacteria. The excess sebum, combined with dead skin cells, plays a significant role in the formation of acne lesions, such as pustules and nodules.

While sun exposure, cold weather, and aging can influence skin health and contribute to other skin conditions, they are not the primary drivers of acne vulgaris. Sun exposure may exacerbate certain skin conditions or scars from acne but does not initiate the acne process. Cold weather generally does not play a role in the development of acne, as hormonal changes are the key factor. Aging can affect skin texture and overall health but typically does not induce acne in the same way that hormonal changes do during the younger years.