The relevance of sebum composition in the etiopathogeny of acne

Acne vulgaris is an inflammatory disease that develops around the hair follicle. Many are the interconnected etiopathogenic factors involved, among which we can mention the increase in levels of androgen hormones, sebum hypersecretion, follicular hyperkeratosis with microcomedo formation, the proliferation of the bacteria Propionibacterium acnes ( P . acnes ) and the resulting inflammatory response. The way this bacterial growth occurs and how it is connected with the development of the inflammatory process have been themes of many clinical and experimental trials. Modifications in the sebum composition lead to a greater proliferation and differentiation of keratinocytes that obstruct the follicular ostium and favor the formation of comedones. On the other hand, these modifications alter the follicular hydration and facilitate the proliferation of the P . acnes , which not only produces chemotactic factors but also releases lipase that oxidizes the squalene. The oxidized squalene induces the formation of pro-inflammatory cytokines and boosts the innate immunity of keratinocytes and sebocytes, thus generating the inflammatory process. The aim of this study was to review the literature regarding the new concepts on the pathogenesis of acne.