Acne and Environmental Factors

Acne is a multi-factorial skin disorder of pilosebaceous unit, and environmental exposures play an important role in etiologies of acne, which leads to a group of environmental factors-related acne such as dioxins-induced chloracne, coal tar acne, cigarette smoking, and ultraviolet (UV)-related acne. Generally, these clinical features of environmental factors-induced acne are similar and characterized by non-inflammatory comedones or cysts with less inflammatory lesions, which has big difference from acne vulgaris. The exact mechanism of environmental factors on human skin and acne are still unclear completely. AhR signaling pathway may mediate the action of environmental factors on the pilosebaceous unit, including accelerating terminal differentiation of keratinocytes and switching the differentiation of sebaceous gland cells into keratinocyte-like cells, as well as the reduced lipogenesis of sebaceous glands. Environmental factors-induced acne is quite resistant to conventional therapy and the only effective management is to remove the induced factors. A better understanding and research of how these exogenous factors works and how they contribute to the physiological function of sebocytes, hyperkeratinization, modulation of skin microbiota, initiation of the innate immunity and inflammatory cascade thus leading to the deterioration of acne are needed in the future.