Does pollution make acne worse?

In 2010, the Global Burden of Disease Project estimated the prevalence of acne at 9.4%, making it the eighth most prevalent disease worldwide.¹

Acne and pollution: an epidemiologically evidenced link³

Two studies conducted in Beijing in 2016 showed that increased ambient air concentrations of some of the most important traffic- and industry-related pollutants (PM2.5, PM10 and NO2) were associated with:

• An increased number of outpatient visits for acne.
• Increased sebum secretion and higher number of acne lesions.

Together, they indicated that exposure to air pollutants may aggravate acne and emphasized that not all air pollutants have the same effect on acne-prone skin.

In addition, a third study conducted in two industrial areas in China (Shanghai and Guangzhou) supported the pathophysiological links between acne prevalence and high ambient pollution levels.³

How might pollution make acne worse?³

Inflammation’s critical role in the development and progression of acne is now recognized. There is growing evidence that outdoor pollution acts as an inflammatory mediator, exerting its effects by generating oxidative stress via Reactive Oxygen Species (ROS) and inflammation. However, the exact mechanism remains to be clarified.

Various hypotheses have been proposed to explain how the detrimental effect of pollution starts:

• articulate matter (PM) have an indirect effect by an outside-inside signalling pathway and recently it has been suggested a direct action by penetration through the stratum corneum.
• Ozone (O3) increases cytochrome P450 activation via Aryl hydrocarbon Receptors (AhR).
• Once in the skin, ROS cause a lipid peroxidation cascade, which stimulates the release of other proinflammatory mediators from keratinocytes, thereby establishing a vicious inflammatory cycle with infiltration of other potentiating cells such as neutrophils and other phagocytic cells.
• Polycyclic aromatic hydrocarbons, commonly found in air pollution, induce an inflammatory response.
• Finally, AhR activation potentiates inflammation, which could increase acne.
• Such stress could overwhelm the skin’s natural defences, depleting its antioxidant capacity, contributing to an underlying inflammatory environment and disrupting the skin’s barrier function.

Such stress could overwhelm the skin’s natural defences, depleting its antioxidant capacity, contributing to an underlying inflammatory environment and disrupting the skin’s barrier function.

UV exposure has a harmful interaction with airborne pollutants:

• UV irradiation compromises the skin barrier and pollutants seem to heighten the phenomenon by disturbing the stratum corneum lipid constituents known to be critical determinants of the barrier function.
• UV exposure and pollutants have an effect on antioxidant depletion and lipid peroxidation levels, which could in turn worsen the effects of these stressors.