Acne is caused primarily due to the blockages of pores on the skin. These blockages stop the oil (sebum) from draining to the surface of the skin. Bacteria grow in these blockages, which lead to an infectious inflammation of that area; this is known as acne. Several factors contribute to the development of acne. These may include hormones, diet, evolutionary biology, vitamin deficiency, and stress, among others.
Acne is a disease of pilosebaceous units in the skin. It is thought to be caused by the interplay of four factors. Excessive sebum production secondary to sebaceous gland hyperplasia is the first abnormality to occur. Subsequent hyperkeratinization of the hair follicle prevents normal shedding of the follicular keratinocytes, which then obstruct the follicle and form an inapparent microcomedo. Lipids and cellular debris soon accumulate within the blocked follicle. This microenvironment encourages colonization of Propionibacterium acnes, which provokes an immune response through the production of numerous inflammatory mediators. Inflammation is further enhanced by follicular rupture and subsequent leakage of lipids, bacteria, and fatty acids into the dermis.
